On iOS the situation has become more complicated, as the redirect can work depending on the app used to open the html file. In my experience, Onedrive and Dropbox work (though onedrive won't let you share the redirected file), but Files, Notes, and Google Drive won't. Alternatively, you can always save the file somewhere (locally on the device or in some cloud provider or network drive) and create a shortcut which follows these instructions for it to open in safari (just as if you had saved it and opened it from Dropbox): https://www.reddit.com/r/shortcuts/comments/p3wm9a/comment/h8v42as/?context=3
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Of course, this only applies if you don't upload the file to some webserver that will render it normally, in that case it will redirect just fine.
MANY thanks for this information! I'm in the process of researching the best method to convert 13,000+ bookmarks from Chromium's JSON bookmarks file into a .url file for each bookmark, preserving folder structure. (Yes, it's probably an insane number so this is part of my effort to help in minimizing and simplifying my bookmarks situation).
I've seen several approaches but none seem to match my needs (*fairly* minimal, but including "as simple as possible"...) precisely enough. Partly because I don't know Python, JS, etc., haven't worked with VB & SQL databases for 19 (!) years, and haven't parsed with GW Basic since, well, even longer (and I don't think it's practical - if even possible - to use it). So I need to learn a language that will be the simplest application for the job.