https://github.com/gildas-lormeau/SingleFile?tab=readme-ov-f...
About 10 years ago I searched and found a webarchive to MHTML converter from someone's small site. I recall there was one caveat, something like it didn't include the date in the metadata of the output MHTML.
Sorry I don't have the link on-hand, it'd be on the HDD I pulled from my old Macbook.
Edit: found an alternative script from my notes: https://blog.iefdev.se/2016/01/converting-webarchive-to-mht/
Edit 2: pretty sure this is the original converter, since I noted a caveat that it outputs the timestamp of the conversion not the time the file was originally saved (the script above handles this correctly otoh). https://langui.net/webarchive-to-mht/
At least last time I checked in only worked for local paths (file://) and only some browsers. Otherwise it would either try to download or just show plain text.
I ended up using Chrome to dump to MHTML [1] and then reshuffle the content into individual files, rewriting the path references and fixing mime types [2]. That gives a reasonably faithful static capture of a page that can be shared as link.
[1] https://chromedevtools.github.io/devtools-protocol/tot/Page/... [2] https://github.com/lacop/udrb/blob/master/app/src/chrome/mod...