$ keyctl show
Session Keyring
 995212359 --alswrv      0     0  keyring: _ses
 869008619 --alswrv      0     0   \_ user: testuser

$ keyctl show @u
Keyring
 853797413 --alswrv      0 65534  keyring: _uid.0
 718614445 --alswrv      0     0   \_ user: testuser

$ keyctl request user testuser
869008619

$ keyctl add user testuser Secret.123 @s

$ keyctl add user testuser Secret.123 @u

$ keyctl print %user:testuser
Secret.123

$ keyctl print 869008619
Secret.123

$ keyctl clear @u