Which ones? Honest question. I only remember games for which GOG apologizes in their store page for missing cosmetics or extra features because originally tied to online services (e.g. the Mafia or Yakuza games), or ones in which they are unlocked by default for the same reason (e.g. Dragon Age Origins).
As far as I remember, the only games which optionally need Galaxy running are those will online multiplayer, and only if you want to play online. This is because the original developers shutdown their own servers for matchmaking or originally used Steam servers for that. GOG servers are only replacing those.
The DMA subsystem maintainer has some reasons: at this time you can disable all rust drivers when building the Linux kernel but you cannot disable rust wrappers to C language APIs. So if you need to change for example the DMA APIs, you also need to fix the rust wrapper before submitting the C patches otherwise you cannot even build a C only kernel.
> The question may be silly, but how does GOG handle multiplayer ?
It depends: some games implement multiplayer through their publisher's private servers (e.g. Paradox games) so users can play together regardless of the shop they bought the game from. Some others (e.g. Dying Light) reimplement multiplayer replacing Steam facilities with GOG Galaxy. In that case interoperability is not possible maily because GOG Galaxy doesn't implement the same anticheat system. Finally some other games whose multiplayer is based on Steam, had the multiplayer removed in the version sold on GOG (e.g. modern XCOM games).
> Also, their list is sadly quite limited it seems, for the games many play.
Nowadays the game market offers more than just AAA games and for people like me who stopped buying DRM-protected games and are not interested in multiplayer there are still many good games to enjoy. Some AA and AAA games are also published on GOG after a while, so it's just matter to wait and support GOG's business model if you don't like DRM.
As far as the Wikipedia definition of it goes, yes it is a "weak copyleft", but that basically means that the license on code and patents is liberal, while license on trademarks is not. That is to prevent bottom feeders to take for example Firefox and LibreOffice, rebuild them with adware and malware and redistribute new installers as "Super Firefox", "LibreOffice Improved" or other misleading trademarks.
Well, LibreOffice is not "copyleft" licensed. It is distributed under a joint of licenses: GNU Lesser GPL v3+ and Mozilla Public License v2. The latter is not "copyleft".
OpenOffice and LibreOffice are already "merged". In fact in the past years, after the fork, LibreOffice developers regularly tracked OpenOffice source code repository and merged all the useful changes they could find, by either picking the original code or re-implementing it their own way.
In addition to that they also completely overhauled and simplified the build system, removed tons of dead code and translated German comments which where there since StarOffice, replaced Java components with equivalent ones written in C/C++, are in the process of switching from GTK2 to GTK3 (mandatory to get Wayland support in Linux), etc. Doing so they made the LibreOffice source code base sustainable on the long term and lowered the difficulty entry level for new contributors, while apparently OpenOffice buildbots are not even able to rebuild their software since last year...
The only useful asset which remains to OpenOffice is the trademark.
They already discussed about this few years ago, but they decided against a date-based versioning because that would have meant breaking a lot of scripts and programs doing kernel detection assuming the old scheme. [1]
OpenSSL package maintainer for SUSE says openSUSE/SLES will stay with OpenSSL (plus handpicked commits from LibreSSL repo), because of missing FIPS and other questionable commits in LibreSSL.