The latest version of MC is replaced with a modified one

After another visit to the launcher, I saw that the latest version was replaced with a modified OptiFine. This isn't the first time this has happened, and I didn't put any effort into it (other than installing OptiFine). However I still can't configure or delete this version.

Translate (with GT):

Последний снапшот - Last snapshot

Последняя версия - Last version

Удалить - Delete