Sort of related to my other post (see: https://www.gog.com/forum/general/gog_and_the_unusual_versioning_number_system ) -

When a game has something new - there's the "Updated" little notice at the top (so it might say Updated 17), so you know 17 games have updates.

Now, 9 out of 10 times, the "update" is actually the installer. But what would be nice is - similar to when a game has an "update" and has that blue circle - if whatever was "new" inside of the game (when you click to expand it and show the executable(s) and any bonus stuff) - if whatever was new also had that blue circle.

Like I said, usually it's the executable(s) that is "newly updated" - but sometimes MP3 tracks are added, or a manual is added, etc.

Just spitballing an idea. :)

If you goto the game page in your library and click more-changelog, it will (well in a lot of cases) tell you what has changed.

No, if a new bonus File (e.g. Russian manual) gets added, the changelog normales won't help you. I think that's what the OP is talking about. So marking the updated file would bei very much welcome.

The blue dot update flag system of GOG, is known to be broken and unreliable for years. [1]

That is why we need:
1. The "what did just update?" thread, which is followed by many GOG users
2. gogdb.org
3. Magog database (only track old GOG games for now)

GOG did try to improve the update flag system in past few years, but the result is still quite bad.

[1] https://www.gog.com/forum/general/the_what_did_just_update_thread/post20713

Really? Thats odd as I am sure I had one just a short while back that the change log told me one of the extra files had been updated. Can't remember which it was.
But I do agree, the whole update system is broken beyond belief, even makes the forum software look fixed. Example, Dying LIght doesn't show updates even though new content is added.
Of course you know what their answer will be don't you, and that is to use Galaxy.

Many GOG games still have no any changelog.
I am sure they have updated one or more times after I bought them.
But no, they just have no changelog.

Correct. That's the idea I was thinking...

And based on responses to the thread - looks like GoG did try to do this, but has not gotten it working.

I've found things added (FLAC files, for example, rather than the original MP3s get added) that have not shown in the Changelog so I see it marked as "Updated" - yet the file version is the same - so I got through the bonus folder and go, "Oh! They added FLAC files for the sound track, not just the MP3s!" (As an example)

It's awesome that they've - at least put in the effort to make something like this. With a huge site like this with so many factors, I imagine it's no easy task to pull off.