the licenses of all "cores" are well documented - i do not see 'duckstation' though
https://docs.libretro.com/development/licenses/

I found that in duckstation git repository:

commit 8f2169339d791be842c3a956765dec9a92a06e73
Author: Connor McLaughlin <stenzek@gmail.com>
Date:   Sun May 16 16:54:44 2021 +1000

    Update news

diff --git a/NEWS.md b/NEWS.md
index 69aeb542..8f4ae0f7 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,6 @@
+- 2021/05/16: Auto fire (toggle pressing) buttons added.
+- 2021/05/10: libretro core re-added. Commercial distribution of the DuckStation libretro core is **NOT PERMITTED**.
+- 2021/05/02: New pause menu added to Android app.
 - 2021/04/29: Custom aspect ratio support added.
 - 2021/03/20: Memory card editor added to Android app.
 - 2021/03/17: Add support for loading **homebrew** PBP images. PSN images are not loadable due to potential legal issues surrounding the encryption.
diff --git a/README.md b/README.md
index 427184a2..6b7c09d5 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ A "BIOS" ROM image is required to to start the emulator and to play games. You c
 ## Latest News
 Older entries are available at https://github.com/stenzek/duckstation/blob/master/NEWS.md

+- 2021/05/16: Auto fire (toggle pressing) buttons added.
 - 2021/05/10: libretro core re-added. Commercial distribution of the DuckStation libretro core is **NOT PERMITTED**.
 - 2021/05/02: New pause menu added to Android app.
 - 2021/04/29: Custom aspect ratio support added.

So it seems related to the commits that add libretro core like these ones:

$ git log 864e7f0c9179ba6e257c7c38022e09708acdfb71..8f2169339d791be842c3a956765dec9a92a06e73 --oneline | grep -i libretro
f98f9fcd CI: Fix libretro dll for Windows
5047a3e9 libretro: Expose support for pbp (and multi-disc)
94cb847e CI: Re-add libretro builds
1392a64a Re-add libretro core

8f2169339d791be842c3a956765dec9a92a06e73 is the previous commit that touched NEWS.md

5047a3e97f3205f7cc1b8e129daed23d529314a0 is also interesting as it's the commit that also adds "libretro core re-added. Commercial distribution of the DuckStation libretro core is NOT PERMITTED." to README.md

So I assume that for some reson duckstation at the time assumed that libretro core had a non commercial use restriction.

I didn't find yet where in duckstation or libretro code where that "Non-commercial" in that screenshot comes from.

In intl/msg_hash_us.h of retroarch we have:

MSG_HASH(
   MENU_ENUM_LABEL_VALUE_CORE_INFO_LICENSES,
   "License" 
   )

So that looks related.

edit1: add of retroarch

I found that: https://github.com/libretro/libretro-super/blob/master/dist/info/duckstation_libretro.info

But I'm not sure how is libretro-super pulled in. Maybe libretro downloads stuff over the internet and has the .info coming from there?

Maybe there is another way where that info is encoded?

Denis.

libretro-duckstation depends on libretro-core-info that has the .info I mentioned before: https://github.com/archlinux/svntogit-community/blob/packages/libretro-duckstation/trunk/PKGBUILD#L11

So we could open a bug there telling that duckstation is GPLv3 and not non-commercial.

In addition it's not possible to be both at the same time, if that's the case it would be illegal to redistribute duckstation as not only it's not possible to satisfy both licenses at the same time, but the GPL also makes it very clear with its liberty or death clause.

In libretro-core-info (https://github.com/libretro/libretro-core-info) we have the following commit:

commit 1accb65482d7905ad2cd9e1c945833a83fd1150a (tag: v1.9.5)
Author: Rob Loach
Date:   Fri Jun 11 17:26:07 2021 -0400

    Update

This changes the duckstation license from GPLv3 to Non-commercial.

We probably need to write to Rob Loach to get more explanations on why it changed.

I'm unsure how to do that in a public way. If I write from my mail address, I would be the only one to receive the response. Should I write the mail with the Parabola dev mailing list in CC?

the code is on github; so "the public way" is as a github ticket - many projects do not even realize that there is another way to communicate about software; and probably never check their email