• an envelope but like, without the top
• ¯\_(ツ)_/¯
• calendars are kind of this shape and this has 31, a day of the month in it
• ¯\_(ツ)_/¯
• folder, it’s their drive app, where you keep files and folders. This one’s actually not that bad.
• the keyhole is used in damn near every password manager, and when it’s not a key it’s a shield of some sort.
• ¯\_(ツ)_/¯

(This whole reply is mostly /s)