Boy, I never looked at it before, but profiles/readme/html/to.xsl looks like a very weird animal. It has templates that match the HTML namespace and ones that match the TEI namespace. That file imports html/html.xsl, which itself imports: common/verbatim.xsl, html/html_param.xsl, and common/common.xsl, which itself imports: common/common_param.xsl, common/common_core.xsl, common/common_textstructure.xsl, common/common_header.xsl, common/common_linking.xsl, common/common_msdescription.xsl, common/common_figures.xsl, common/common_textcrit.xsl, common/common_gaiji.xsl, common/i18n.xsl, and common/functions.xsl I've just looked through all of those (quickly), and none seem to have a template that matches <gi> explicitly. So I think it's probably quite reasonable to just tuck it in here. How would the code in to.xsl get the version number (to point to the Vault)? A parameter? Read P5/VERSION (in which case it needs to be updated before this is run)?
Not sure it does work automatically, one would think that it would follow the same thing that happens with the Guidelines but looking back through some earlier ones I'm not sure it does.
Looking at the makefile which calls the ant script, I think that the release notes are generated using the 'readme' profile of the stylesheets. So:
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%...
If we put a template in to handle tei:gi in that stylesheet that would probably do it. (Anyone else see a problem with that?)
And yes, I think release notes should always point to the Vault of that version of the the Guidelines because if they point to the live site then by next version they might be out of date.