Im using repo tool to manage multiple repositories.
Here is my sample manifest file and I have given a tag name in my revision - 'firsttag'.
When I do a repo sync it says -
Fetching project repo1
fatal: Couldn't find remote ref refs/heads/firsttag
<?xml version="1.0" encoding="UTF-8"?>
xml file
<!-- <default revision="refs/heads/master" -->
<default revision='firsttag'
remote="github"
sync-j="4" />
<project name="repo1" remote="github" path="repo1"/>
<project name="repo2" remote="github" path="repo2"/>
</manifest>