a:<action> - Restrict the lookup to a certain action
For example, if you wanted to only rollback blocks placed, you would use a:+block
Here's a list of all the actions:
a:block (blocks placed/broken)
a:+block (blocks placed)
a:-block (blocks broken)
a:click (player interactions)
a:container (items taken from or put in chests, etc.)
a:+container (items put in chests, etc.)
a:-container (items taken from chests, etc.)
a:kill (mobs/animals killed)
a:chat (messages sent in chat)
a:command (commands used)
a:session (player logins/logouts)
a:+session (player logins)
a:-session (player logouts)
