MattZ (npub1rsgβ¦an77)
Nonfree components like Linux, also it's the only email client (that isn't completely proprietary) that has implemented non-IMAP/SMTP standard email support for FAGMAN email substitutes which is questionable, specially considering the influence it has.
I can bet GNU/ηΏ ζη³ (npub1x2vβ¦ar98) can further elaborate.