The script is agnostic of the utag.*.js. It creates a html with only the utag.js path for the configured envs and does a get. From the response it extracts the utag.*.js source paths and does a get on each of them.
Based on a config file, it tries to guess which tag the utag.*.js file is for and renames it thus - e.g. utag_SiteCatalyst.js. The guess is based on the tag's CDN url. If it cant do it, it just names it as utag_0.js, utag_1.js etc. I guess if this happens, we lose numbering.
Basically it behaves just like our site does, in a stripped down manner.
We have instrumented our load rules so the request can run against all tags.
Hope I am not missing anything.