Mention the PID in the documentation for Mojo::Log?

[ajmetz]

Was reading:
https://docs.mojolicious.org/Mojo/Log#format
and wasn't sure what the value between the time and the level was in the example log messages.
Had to go into the source and saw $$,
and then looked that up, and saw it returns the process id.
So assumed the number was the PID.
Then I double checked, via both ps at the command line of one of my Mojolicious apps,
and the PID in the log message when Plack kills and restarts the same app on a file change due to the -R flag having been used with plackup, and yep, now I know it's definitely the PID, =).

Could that be mentioned in the POD somewhere?
Perhaps in the format section?
https://docs.mojolicious.org/Mojo/Log#format

Or is this super obvious due to widely accepted logging conventions, I was unaware of?