Will this be a solution that bypasses a need to have an extension (like Timimi) for local saves using a browser as editor?
IF so, will further progress be added to this thread? And if not, how can I receive a notification for this?
The OP uses the default browser save mechanism, which is activated by the green [Download] button at GettingStarted.
TiddlyWiki uses browser extensions like TiddlyFox (now obsolete) and Timimi since a very long time already, so we (the TW users) are used to use “single click” save options. We are not used to use the browser default saver, which needs several clicks instead of one.