I don't know but OP's comments history is funny, it's a lot of our own emojis but displayed like they appear on other instances: huge
Many users regularly mass delete their entire post history's and switch accounts. I dunno if that's why the post was deleted, but every post and comment made by @EmotionalSupportLancet@hexbear.net is gone now, so they mass deleted their posts/comments (including the emoji post) Don't know anything more than that.
I noticed but at least you can view the post still by looking on another instance
You may be able to find them in the Github (https://github.com/hexbear-collective), but iirc the move from federation changed things so they may not be there anymore.
Carcosa may have a list of sorts?
The custom emojis are stored in the DB, not the source
This atrocity will output a list of all custom emojis with their shortcode and the URL of their image by fetching the present post
There appears to be 1978 of them, which is insane lmao