+1 for all the ones from me

Is there any reason not to use the SPDX license IDs here? => https://spdx.org/licenses/ (e.g. GPL-2.0+ in this case).
In any case, this patch makes things way better, so +1 from me :-)

Is there any reason not to use the SPDX license IDs here?

The values are the ones in KAboutLicense from what I can tell.

Yeah, legacy reasons. I am looking into ways to change this moving forward though. Not sure if the cost-benefit will be reasonable, but it's on my radar and at a glance should be doable in some form or fashion.

Starting version 2.0, it is no longer valid to use the + operator in a license identifier

should we address it?
https://en.wikipedia.org/wiki/Software_Package_Data_Exchange#Deprecated_syntax

These aren't SPDX identifiers but kaboutlicense keywords https://api.kde.org/frameworks/kcoreaddons/html/kaboutdata_8cpp_source.html#l00397

In D6628#676720, @sitter wrote:

These aren't SPDX identifiers but kaboutlicense keywords https://api.kde.org/frameworks/kcoreaddons/html/kaboutdata_8cpp_source.html#l00397

Makes sense.
@bam As far as the "legacy syntax" is concerned: SPDX broke their conventions multiple times, so on the AppStream side I really got sick of these breaking changes and any syntax is fine. On the KDE side, switching the kaboutlicense keywords to SPDX is probably a bigger endeavour, and may not actually be worth the effort (I would guess that there may be some break risk here). So, this change looks fine to me now, as it is :-)

Thanks for clarifying.

In D6628#676721, @mak wrote:

So, this change looks fine to me now, as it is :-)

And yet it was changed again! :-D
https://github.com/KDE/plasma-desktop/commit/05c230733a1b9d16c0e52eb54955c62d340b94e3

In D6628#676722, @bam wrote:

Thanks for clarifying.

In D6628#676721, @mak wrote:

So, this change looks fine to me now, as it is :-)

And yet it was changed again! :-D
https://github.com/KDE/plasma-desktop/commit/05c230733a1b9d16c0e52eb54955c62d340b94e3

:-D - *That* change also looks good, and apparently it doesn't break anything. The "GPL-2.0+"-style identifiers are encouraged by AppStream as much as "GPL-2.0-or-later", but "GPLv2.0+" is considered legacy. Its curious that AS would even validate this stuff though, as it doesn't look into desktop-entry files (but maybe some auto-generation is at play here).