BUR #3181 has been approved by @evazion.
remove alias alternate_outfit -> alternate_costume
If this BUR is approved then I will submit a follow-up BUR as follows:
alias alternate_costume -> alternate_outfit
alias adapted_costume -> adapted_outfit
Quite often the "costumes" being tagged are just regular clothes, which are not costumes. Changing the tag names to "x_outfit" gives a better sense of what the tag is for.
As for alternate_costume's wiki, it currently reads as follows:
A character wearing a (typically fanmade/unofficial) costume other than the one they are typically depicted in.
For a game character, this is a costume other than the standard, one that can be unlocked within the game.
This is a poor description. The wiki is trying to describe it as a tag for unofficial fan-made outfits, but it then mentions it is also for any non-standard outfits, such as alternate skins in games like Azur Lane. This second sentence poses issues when trying to decide which outfit is a character's "standard" outfit - take a character like Aoi Itsuki. He has two main outfits, his school uniform and his stage costume. Which is the default "standard"? Is it the one he wears 90% of the time, or the one on the cover of the game? There's also The Legend of Zelda: Breath of the Wild, where Link has no starting outfit and there are many different sets of clothing available throughout the game.
I believe that rather than game skins, this tag should be for outfits that a character has not worn in any official media. Such a definition leaves little room for subjectivity and feels in line with what the tag was originally supposed to be used for. If people want a tag for game skins then I wouldn't be opposed to the creation of something like alternate_skin, but as it stands I don't think alternate_costume/alternate_outfit is particularly useful when it's for both at the same time.
EDIT: This bulk update request is pending automatic rejection in 5 days.
EDIT: The bulk update request #3181 (forum #170635) has been approved by @evazion.
Updated by DanbooruBot