I published a gemini capsule on srht.site including a .txt file, but pages.sr.ht serves it as text/gemini instead of text/plain. Using the gmni client to test:

$ ./gmni -i gemini://elly.srht.site/d/blog/2022-01-18-backups.txt
20 text/gemini
[body text...]

this is surprising since there appears to already be code to handle this case: https://git.sr.ht/~sircmpwn/pages.sr.ht/tree/master/item/server.go#L300