A term used similarly to Friend of Dorothy, a Friend of Mara is a code word used to describe someone in the LGBTQ+ community. The name "Mara" comes from the 2018 She-Ra reboot.
"Friend of Mara" comes from the TV show "She-Ra and the Princesses of Power"
While it is used as a password to unlock certain holograms and such in the show, it is also slang for being a member of the queer community within the fandom.
Queers (mostly lesbians) ask if you are afriend of mara when they want to know if you are queer as well.
Long time ago they used 'friends of Dorothy' but the crew-ra brought this back again:)