gitea.scheme.org had accumulated a bunch of spam accounts made by
automated web crawlers. I just deleted them:

Ronald_Tolkien        xxxxxx@gmail.com
austingale            xxxxxx@candassociates.com
jamesandersan         xxxxxx@gmail.com
jonemarsh12           xxxxxx@gmail.com
lucassmith            xxxxxx@gmail.com
nehasingh4k           xxxxxx@gmail.com
pressreleaseprovider  xxxxxx@gmail.com
raichampl             xxxxxx@outlook.com
samfisherr3055        xxxxxx@gmail.com
smithjohn98           xxxxxx@ffo.kr

I also enabled CAPTCHA in the Gitea configuration. This will hopefully
block new spam accounts from being created from now on.