authorized_keys(5) on Linux
The text a3e06b0bb5f7, as Debian 9 (Stretch) shipped it.
OpenSSH SSH daemon
Flags it lists
-
-4 -
-6 -
-C -
-D -
-E -
-T -
-c -
-d -
-e -
-f -
-g -
-h -
-i -
-o -
-p -
-q -
-t -
-u