Commit 611cfc85c531 ("T6173: validate allowed characters in ISO image name") missed the probability that version is a dict member bot empty.
Building custom VyOS version: 1.5-asdf%-202404081841 I: Checking if packages required for VyOS image build are installed Version contained illegal character(s), allowed: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.-+
to avoid a mix of image build scripts and ancilliary scripts in the same directory