Is common when using git to leave some machine-parsable and human guessable strings in the form of ":"-separated "key: value" strings.

topic: Short commit subject

Commit description spanning multiple lines while
staying bound to the 79col limit.

Bug-Id: 1234
Sample-Id: 00000000-zzuff

In Libav we leverage the following:


Topic tags should be single words referring to the area of interest followed by :. Example: a patch introducing a codec could have tag lavc:; subsequent patches could use the codec name e.g. h264:. Tags should not contain / and multiple can be added e.g. x86: h264:


Use the bugzilla bug id to refer to the issue fixed by the commit. Third party trackers should use a name prefix and a slash (vlc/1234 or videolan/1234 for example).


To make sure the patch is backported to the ReleaseBranch.


When fixing a Security issue refer to the sample solving the issue by its Sample-Id when available.

Sometimes we receive informal/private reports by known individuals, use the tag to refer to them.