id-utils 4.6.28-20200521ss15dab (amd64 binary) in ubuntu noble

 Actually, the term `identifier' is too limiting--`mkid' stores
 tokens, be they program identifiers of any form, literal numbers, or
 words of human-readable text. Database queries can be issued from the
 command-line, or from within emacs, serving as an augmented tags
 facility.