This may be a dumb question because I don't understand the concept of session keys well enough and neither have extensive experience using shell loops: in substrate one finds this comment telling us how to generate keys for a network:
# stash, controller, session-key
# generated with secret:
for i in 1 2 3 4 ; do for j in stash controller; do subkey inspect "$secret"/fir/$j/$i; done; done
#
# and
#
for i in 1 2 3 4 ; do for j in session; do subkey --ed25519 inspect "$secret"//fir//$j//$i; done; done
In do for j in session
what is session
and how does one get it?
Is it some sort of secret
such that for one authority three keys distinct derivations are generated like the following?
$secret/stash-secret
$secret/controller-secret
$secret/session-secret