Depending on the activities, the icon will be shown.
when a new issue is added
when an issue is updated
when a comment is posted
when a Wiki page is updated
when a file is added
when a file is committed on Subversion
(Commits to external repository will not be shown.)
when a repository has been created in Git
when a branch has been created/deleted in Git
when a tag has been created / deleted in Git
when changes are pushed to a branch in Git
when a pull request has been added, or a comment has been posted on the pull request
when a comment is added to apull request
when an issue has been deleted
when a Project member has joined or left
When version/milestone is added
When version/milestone is updated