The only REL_SE file meant for configuration is REL_SE_Config.txt, if you don't use MCM. All other files are meant to be read and written by the script only.
Check the Documentation tab for the latest version of the config file. Either copy paste it to your config, or delete your current one, a new config will be made once a save is loaded.

Below is the explainations of what each configurable variables in the config file do:
*all rates assume you have given the value in percentage, so cosmetic=50 means it's 50/50 to drop, you can add decimals into them, maximum is 15, more can be added but the script round them to 15th anyway.

Dice size : determine the maximum number randomly generated, it's always between 1 and Dicesize. This number is used to determine whether or not you receive a loot and if so which rarity
Cosmetic: the drop rate of items flagged as Cosmetic manually by users in Rilissimo's generator mod
Uncommon:  the drop rate of items flagged as Uncommon in Rilissimo's generator mod, automatic or manual
Rare: same as above, but with rare
Veryrare: same, with very rare
Legendary: same, with legendary
* Cosmetic drop rate is independent from the other 4, the mod by defaul gives you a 25% chance (total of uncommon to legendary) of getting anything whenever it is triggered, it can go up to 100 and beyond, with 100 being you're guaranteed to get 1 item, >100 your uncommon rate suffers.
*Example: 25 / 10 / 7.5 / 5 / 2.5 : you open a chest, you have (10+7.5+5+2.5) = 25% of getting at least an uncommon item, 75% of nothing. In addition to that, you have 25% of getting a cosmetic item.
100/ 50 / 25 / 25 / 25: you ((50+25*3) > 100) are guaranteed to have an item, but since their sum is above 100, your uncommon drop rate is only (100 - 25*3) = 25%, so you have an equal chance of getting an item of any tier, in additional to a guaranteed cosmetic item (100%)

Lock loot across saves: Lock the randomly generated loot to a container the first time you open it and trigger REL_SE, subsequent reloads to any point prior to opening such container will always yield the same loot for said container.
Since this has to work outside of game save data, the locks have to be reset manually when you start another playthrough, else you'd get the same item in said container on your new playthrough too.
To reset all locks, press Reset Loot List in the optional tab,* either while on the Nautiloid without having any XP yet, or anywhere else while having 13 gold in the inventory of the character you're currently controling (as long as either of the conditions is present, this will not reset your entire loot list to a new state, just clear all locks)

Maximum number of items processed for a given rarity-type: Limit any rarity-type list of item to the shown number to avoid script lag on play throughs with large numbers of item in LootList.txt, this in turn limits the pool the item can be drawn from to (maximum) 40 times the shown number (10 types * 4 rarities)

Make cosmetic items unique : While this is enabled, any cosmetic item you loot will be permanently removed from the pool. Caution: disabling this option after looting cosmetic items will not bring them back.

Clear Container's gear if duplicated: the loot in containers that have not been touched will be checked against your party inventory and camp chest, if REL_SE has injected the item before, the duplicate in the chest will be removed
Return an item of equal rarity for every deleted item above: if enabled, will add a REL_SE unique gear for every removed gear from the option above.

Allow cosmetic in chests : enabled by default. With this off, no cosmetic item will spawn, unless the container is a wardrobe
Cosmetic rate penalty : Determine the reduction of cosmetic drop rate to anywhere other than wardrobe:
default is 25, meaning the drop rate is reduced by 25%, taken from general cosmetic rate. Set to 0 to disable. set to 100 to completely block cosmetic from appearing anywhere other than in wardrobes.
There are 3 wardrobe category, sorted from least to most likely to spawn cosmetic: Shabby Wardrobe, Wardrobe, and Mahogany Wardrobe, 
Cosmetic rate for Mahogany Wardrobe : 
Cosmetic rate for normal Wardrobe 
Cosmetic rate for Shabby Wardrobe 
*The options in this tab are superceded by Go Ham mode / AnyContainer. except general cosmetic rate

*The options below requires choosing Consumables Randomization in the generator to take effect in-game)
/ Rate penalty on chests: Rate penalty for consumables to spawn in chests,100 means no penalty, 0 means 0 consumable drops in chests
PotionRepeatable, ScrollRepeatable, ArrowRepeatable: Enable multiple rolls per container opening for potions, scroll, arrow
PotionTotalCount, ScrollTotalCount, ArrowTotalCount: Set maximum number of multiple rolls
PotionPenalty, ScrollPenalty, ArrowPenalty: Set stacking rate penalty for each consecutive roll success
PotionHealingRate: Determine the rarity of healing potion, example: setting to 50 means there's 50% chance the generated potion to be a healing potion, 50% chance to be 1 of any other potion in the same tier.
* Healing potions are divided into 4 rarity categories: normal variant for common, greater for uncommon, superior for rare, supreme for very rare

Say you enable P_repeatable, set P_total_count = 3, P_rate_multiplier = 10, and P_common = 50 (assuming anything else is 0)
+ 1st roll you have 50% chance of receiving a common potion
+ if success, move to 2nd roll, you now have 50*(1-10/100)=45% chance for a common potion
+ if success again, move to 3rd roll, now with 45*(1-10/100)=40.5% chance
- generation over once 3rd roll is done or if the roll fails at any stage

I set book shelves and books to be possible triggers for scrolls, bottle racks for potions, and barrels for arrows. looting chests will trigger roll of 3 of them, with penalty depending on Usable_Penalty. Boss looting and mechants also get triggered, but without penalty
 
The logic order is as follows:
regardless of EnableChestSpecific being on or off:
If  EnableNormalCosmetic is off, and the container is not a wardrobe but a chest, and AnyContainer is off:
generate cosmetic with reduced rate
If the above is the same but the container is a wardrobe:
generate cosmetic with input rate depending on which type of wardrobe it is
If the container is not chest nor wardrobe and AnyContainer is off:
no loot
If AnyContainer is on:
cosmetic by general rate + unique loot

Trader Setting tab
Enable Trader Shuffle : Enable to allow traders to switch items currently on sale with other times in REL_SE generation pool. Only unique items given to trader by REL_SE are affected by this. This doesn't affect sold items. By default will ignore items the traders originally has.
Enable Randomized Shuffle: By default shuffling will retain the rarity distribution of shuffled items( 4 uncommon, 3 rare go in, 4 uncommon, 3 rare go out), enabling this option will make the item draw random, according to the global rates scaled to 100%.
Long Rest shuffle amount : How much of the total eligible items get shuffled, 100% means all of it, 0 means no shuffling on long rest, this is a chance-based setting, so 50% means most of the time 50% of the eligible items are expected to shuffle, it's not guaranteed, maybe more or less.
Short Rest shuffle amount : Same as above, but with Short Rest
Include original gear items : Enabling this will include the items traders originally has into the shuffle list, they must still have unique tag to be eligible.
Include Sold Items  : Same as above, but with items you sold too
Include Non-unique Items: Disable the unique flag check, allowing any equippable item of uncommon rarity or higher to be shuffled, depending on the 2 settings above.
* This doesn't take effect until the first time you take a rest with the new version installed, only proc once per rest.
* Expect non-integrated mod items to be ignored by this, since they often don't have unique tags, REL-integrated items and vanilla non-common items (except the +x armor/weapons) are safe. Unless you include them too.
*Sold item shuffling has a conundrum: either no sold items, or yes sold items but whatever item shuffled out that you looted will be returned to generation pool, so you have a chance to find an item twice or more, but no 2 at the same time from REL_SE at any point. I can't find a way to tell items you sell to traders and items shuffled in apart.
* On the plus side you now have 2 ways to recycle useless gears: either use Sacrifice for a guaranteed chance of 1 gear in exchange for useless ones, or use Shuffling to have traders switch your sold items with another, but you have to buy it.

Drop rate randomization: set to 1 to allow randomization of the 5 drop chance above, up and down to the values min and max, doesn't work if the chance is 0
min: the lowest possible new rate, scaled by <drop rate>*(1+min), so if your min = -0.5 your lowest possible rate value is half the original
max: the highest possbile new rate, scaled by <drop rate>*(1+max), so if your max = 1 your highest possible rate value is double the original
*Example, you have 5% to get a legendary item, you enable this feature and set min=-0.5 and max=1, the new chance for a legendary item would be anywhere between 2.5% and 10%

Enable randomization scaling: scale the drop rates back so they always sum up to maxTotal below, set to 1 to enable
Sum for scale of randomized drop rates: the maximum allowed total chance that an item can drop, so if your random chances sum up to 150 and your maxTotal= 75, it will cut all chances by half, doesn't work on cosmetic rate
* note that with Scaling enabled some rates may go below your setup min or above your max.

 Enable setting in Chest-based drop rates tab: set to 1 /tick to enable, the mod will adjust the drop chance of chests based on their name, currently sorted into 3 quality tier: poor, normal , good, adjustable below:
1cosmetic
2cosmetic
3cosmetic
1uncommon
2uncommon
3uncommon
1rare
2rare
3rare
1veryrare
2veryrare
3veryrare
1legendary
2legendary
3legendary
* 1 is poor, 2 is normal, 3 is good, you should get the pattern by now
*only support vanilla chests, or modded chests that use vanilla names

Enable Weighted Drop : set to 1 to enable,, your chance of getting a particular type of item is determined by the variables below:
*if a selected type doesn't have an item, the script will switch to another type randomly until it has found 1 on the same rarity tier
*if a selected rarity doesn't have an item, the script will go down 1 tier and repeat the search.
* by default if disabled: Items are divided into rarity tiers. Within a tier, there is no balance of which type an item can be pulled. That means if you have a total of 10 shields and 100 weapons distributed to REL_SE, the weapons are 10 times more likely to be picked compared to shields due to sheer number.

ringsrate / ring drop rate
amuletsrate
bootsrate
glovesrate
cloaksrate
hatsrate
shieldsrate
weaponsrate
narmorrate
clothesrate

Notice all of them add up to 100 by default, the total rate can go either way,but <100 or >100 your highest type rates suffers, similar to the example above

Level-based loot settings Tab
*If enabled, will override equippable item rates from other tabs
Level Ceiling : The last level you want the rates to change, levels above this retains the rates at the ceiling
Level Floor: The first level you want the rates to change, levels below this retains the rates at the floor
Formula type:
+Linear: Drop rate changes at a constant rate from Ceiling to Floor, default, basic
+ Quadratic 1D: Drop rate changes more the higher the level is, from Ceiling to Floor
+Quadratic 2D: Create an addition middle Level-Drop rate option, drop rate change is different between Floor to middle and middle to Ceiling (useful if you want a certain rarity to increase up to a point mid-game, then decrease for other rates late-game) 
... starting rate: Drop rate at Level Floor
... ending rate: Drop rate at Level Ceiling
Example:
Celing = 12, Floor = 1, Uncommon starting: 25, Uncommon ending: 10
+Linear: Uncommon drop rate decreases by 1.364% each level from 25% at lv 1 to 10% at lv 12
+Quadratic 1D: Uncommon drop rate decreases slowly initially, but becomes faster at higher level
  (25% -> 24.88% -> 24.5% -> 23.88% -> 23.02% -> 21.9% -> 20.54% -> 18.93% -> 17.07% -> 14.96% -> 12.6% -> 10%)
+ Quadratic 2D: Depends on 3rd Level-Rate point
50% at Lv 6 -> (25% -> 34.24% -> 41.36% -> 46.36% - > 49.24% -> 50% -> 48.64% -> 45.15% -> 39.55% -> 31.82% -> 21.97% -> 10%)
5% at lv 7 -> (25% -> 19.7% -> 15.18% -> 11.45% -> 8.52% -> 6.36% -> 5% -> 4.42% -> 4.64% -> 5.64% -> 7.42% -> 10%)

Show current rates button (bottom of the tab): create a message box giving you the drop rates at your current level and the next



>Optional content, disabled by default<
Rerolling price: If you are short on loot and high on cash, deposit <Gachaprice> amount of gold into a looted chest so you can spin that wheel of fortune again.
*The feature will not trigger unless: the chest has a special debuff preventing you from rerolling AND the chest has the exact amount of <Gachaprice> gold inside it. 
*The modder is a loot goblin himself, so he would never do this P2W shit, unless it's for testing. This is meant to be a joke feature, but it would 100% work, camp chest is excluded from this. 

Pity: Exactly like how Gacha system works: you are guaranteed a legendary item after enough times looting and not getting one. The counter progresses if you don't gain a legendary item (only when the legendary rate is not 0), and is reset on when you get a legendary item, even if the pity count hasn't been reached

Go Ham mode  : by default REL_SE filter objects so only certain chests can trigger the script. Enable this disables that filter, so ANY item considered as 'Container' by SE will trigger instead.

Enable Ritual: If enabled, you are able to trade <SacrificeCount / Number of required sacrifices> number of items of the same rarity for a guarantee chance to get an item of 1 tier higher. Sacrifice item must be non-camp clothes equipments. Doesn't work if you sacrifice legendary items.
To do so, find a chest with REL_SE buff denoting you've already looted it, deposit the exact number of needed items into the chest, close it, open it again.

Loot Dispensing Aura: None: Disabled
REL_SE : will automatically roll the dice on any and all eligible container affected within 15m of the currently controlling character, but looting is still manual
Autoloot Aura: same as REL_SE, but will pick most items into your inventory also
Enable deity-based save scumming countermeasures: you get punished for save scumming to reroll for another item, the severity of the punishment is scaled linearly by the number of items you have rolled in the current save versus the number of items you have rolled in the save you're about to load. Not all of the punishments are scaled

 Enable deity-based insurance policy: you get an insurance scam for deliberately dropping you total chance of getting an item in a chest to 20% or less. You receive a payout when you get nothing from a container/corpse. The magnitude of the insurance payout is scaled linearly by how much  you would go beyond 20% (15%, 10% or less). Not all of the payouts are scaled
*Notice that if you have used up a payout or done a long rest, reloading to a point before those will not trigger it again, unless you go back and open a chest for the first time again, assuming you also didn't get an item AND you received the same payout.

Disable notifications: By default message boxes will appear when you trigger a punishment/payout to give context and clues of why you receive them, set to 1 to turn them off if they annoy you, or if you want to go in blind.

Load/save/loot optimization: (on trial) By default, the mod iterates over all items in Lootlist.txt on save/load to check for invalid IDs and  unique gears the party own and REL_SE has data on it but hasn't dispensed it -> to avoid duplication. More records in LootList.txt = more checking time = longer lag on save/load
By turning this on, the mod instead check for party + camp chest inventory for unique items to see if LootList.txt has any then exclude them, basically doing the other way around.
*Ideally, vanilla method works best the more items you haved looted, since that would diminish the current available pool of items, reducing the lag, and this optional method works best early on when you have little or no unique gear, when the mod doesn't have much to check.
I'll scrap this option if it's even laggier, I'm at 2k6 itegrated items and the process doesn't seem noticably better/worse when turned on/off for me