Both Subversion[1] and CVS[2] had keyword substitution, which replaced those tags with useful information like the commit id, author, date, etc. They were very

Both Subversion[1] and CVS[2] had keyword substitution, which replaced those tags with useful information like the commit id, author, date, etc. They were very useful when you were looking at a source file, to see what version of that file you had. Git had something similar with Git Attributes[3], but AFAIK, they were just references to blob ids, so they never really took off. For git, I now use tags (and versioning based on tags), that more or less replaced svn/cvs keyword substitution in the git ecosystem. [1] - https://svnbook.red-bean.com/en/1.7/svn.advanced.props.special.keywords.html https://svnbook.red-bean.com/en/1.7/svn.advanced.props.speci... [2] - https://www.gnu.org/software/trans-coord/manual/cvs/html_node/Keyword-list.html#Keyword-list https://www.gnu.org/software/trans-coord/manual/cvs/html_nod... [3] - https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes https://git-scm.com/book/en/v2/Customizing-Git-Git-Attribute...