From jpolgesek on the 'core community' Discord:

The game details API - e.g. api.gog.com/v2/games/1436873631 - is returning persistent 429 errors (too many requests) both for my home IP, gamesieve's server and a random online tool I tried, with a retry-after header of 3 seconds. Either the retry-after header or the http status code is 'wrong' here. Plus, y'know, the API is currently unusable. :)

later edit: The API is working fine again now => but it seems that the server restart (?) caused all (?) default goodie names to once again have been lost, as I'm now seeing that issue come back in force.

-=USER ERROR=-

No, it's not. Today is the 5th of September.

OOPS
Well that was embarrassing...

https://www.gog.com/
https://www.gog.com/account

Both URLs are very unstable since yesterday.

Not here.

Everything is fine for me.

Not really something which has "broken", but worth flagging for attention anyway:

A number of ancient Gwent DLCs are being newly (re-?)exposed on the API, with "isAvailableForSale" (still?) set to true and a store href set, so they also can be bought from the store. Given two variations of the starter pack and two products with "TEST PUBLISHER"/"TEST DEVELOPER", this doesn't seem like it's intended. :)
(This is happening alongside countless updates to publisher/developer/size/localizations/os support for many other Gwent DLCs, but those were already exposed on the API and (crucially!) lacking the store href.)

* 2039122211: GWENT: Starter Pack
* 1142753074: GWENT Starter Pack
* 1326039182: GWENT - Kegs - 1x Ultimate Premium Keg
* 1148469859: GWENT - Ornaments - Undying Fire Cardback
* 1733867353: Merchants of Ofir Keg x2

Many games going through something like this lately.
For example - witcher 3, homm4, baldurs gate...
Looks like GOGers are reindex some entries.

Seems like I now got the new front page too, but it's dark even though I have the light theme selected. Please fix that.
Also, not having DRM-free at the top anymore makes me very wary. Remember what happened shortly after fair price worldwide was removed from the front page...

I can only get the new top section of the front page to show in a private window, but whenever I do, it consistently shows me prices in PLN rather than in EUR. I tracked it down to JS attempting to read my preferred currency from local storage, rather than a cookie, and that local storage entry simply not existing.

The update flag (blue dot) is broken intermittently since Sep 8.
Only about 1/3 updates get the flag.

There seems to be something wrong with Master of Magic (the new one) install via Galaxy. Trying to install it fails immediately (about 1.4mb in) with "(E4) Disk access error occurred during installation". No other install has that issue.

I'll five it a day or two before launching official support ticket.