Lol, honestly i'm not very good with gvsbuild, and most of it came from borrowing lines from Cas's gvsbuild fork and doadin's gvsbuild batchfile, so i'm inclined to agree with your confusion
Deletion indeed seems appropriate, as since you say it's deleted anyways in current setup - I added the deletion step specifically to start fresh, but then missed the redundant line you catched here.
Btw, I had another thought, totally unrelated, but just thought I might as well throw out there while posting anyways. I will not make a patch for this to send you, as not working on this project here actively anymore, but I was thinking that instead of downloading latest python and installing and uninstalling upon each job of all the install scripts, then if this was still my project then I would change it over to instead download/use the much smaller
embedded distribution, which is an isolated minimal python environment to include with your windows app(curl/bsdtar pipe
https://www.python.org/ftp/python/3.8.5 ... -amd64.zip to C:\python - 7z(a).exe doesn't support extracting zip from pipe btw, as needed header at end, but bsdtar does, already in default msys64 setup), which is blazing fast to download and unpack(under 8 MiB archive, where most of it's content also is zipped inside, i.e its standard lib), so instant extraction i.e. under 5 secs for both download and extraction in my quick tests), and then use that for each project and simply delete when finished. This also would help people which have python already installed locally, to not interfere with that e.g avoid current situation of there local python getting wiped after a build-script finishes. Lastly, avoids the need of running with admin rights for all build-scripts additionally, as last benefit. Note, embedded archive misses pip, so would need install pip first with "curl
https://bootstrap.pypa.io/get-pip.py | python", and before that line would need uncommenting first "import site" in 'python38._pth', through 'sed' or whatever scriptable tool. Then also the patching lines would need a quick change in the deluge-build scripts and that's pretty much it, mostly. (The embedded python zip is a little bit of a mess with all those PYDs in main folder, but can be made like original python to e.g. have a DLLs folder with them instead, so as to not polutte main dir with all those - that just needs a single extra line added named 'DLLs' under ''python38._pth', though an official windows deluge installer would also have all the needed PYDs in main folder however, so personal choise)
Anyway just a quick thought to might as well throw out there additionally, while anyway replying to direct question asked, for a possible feature idea/suggestion to you, before going back under my rock again
Edit: Not that I'm gonna use it for anything lol, but I've almost finished transferring all my own build-scripts over, as had some free time and just "felt like it" lol
Some things are missing I found in embedded python distribution, compared to full install, like certain headers needed during libtorrent buildings and whatnot, plus for correct gtk building etc, so I changed over to a "nuget" package version of python for that, which I stumbled over, which can be downloaded, unzipped and used portable, just like the embedded distro, so still much quicker and more isolated plus no admin rights needed and then I just use embedded distro for the actual deluge builds but not the components. It was a bigger job than I first thought lol, took much of the afternoon today in total, with so many lines to change, and debugging some pitfalls throughout, and anyway, there's no idea imho in posting patch for this, if interested, because our scripts vary already to much with your changes made, so wouldn't apply properly anyhow, but if interested at any time then give me a shout and I'll send you my scripts for Inspiration to you, to work after - also, I cannot even make patch as thought I had scripts backed up, before I started changing them directly, but didnt(well, I do, but only much older versions), so only have the changed almost finished new scripts now(though could get them back with some quick copy/pasting jobs, and quick edits done, to be able to make patches, but don't really wanna bother since as said will properly not apply on your end anyway and maybe you don't even deem it something you wanna mess with in first place either.