A string that interpolates `%(fieldname)` from the object
pointed at by a ref being shown. The format is the same as
that of linkgit:git-for-each-ref[1]. When unspecified,
- defaults to `%(refname:short)`.
+ defaults to `%(refname:strip=2)`.
--[no-]merged [<commit>]::
Only list tags whose tips are reachable, or not reachable