Moving towards SPDX Compliant Copyright Statements in PO Files

[Andreas Cord-Landwehr]

Hi, following up the discussion in the separate thread ("reuse compliance and 
imported po/"), I need some input about the practical steps to achieve this.

At [1] I have a merge-request prepared that updates Lokalize to:
- understand both, the "old" copyright statements and the "new" SPDX copyright 
statements
- changes to SPDX copyright statements per default

The technical change here is the simple part, but we have to look into the 
translation workflow, where I am not an expert. Essentially, we have two main 
questions on table:

a) Is it acceptable to have a transition phase where we have both kinds of 
copyright statements inside PO files because translators of the same file use 
different tools/different versions of tools that do not yet all support SPDX 
based statements? (please also say if there are more tools additional to 
Lokalize, GTranslator and Poedit that we have to look at)
b) Is it acceptable to only support forward migration from "old" to "new" 
copyright statements and not the way back?

And actually, are you OK with going towards SPDX based copyright statements 
our do you have any fundamental concerns? As Harald already said, it would be 
a very big help for our automatic license/copyright check tooling because most 
of the code already is ported to SPDX based statements.

Best regards,
Andreas

[1] https://invent.kde.org/sdk/lokalize/-/merge_requests/22

PS: Yes, I deliberately only said "copyright" and not "license" for now, 
because "license statements" will be a quite harder problem to tackle because 
it is probably not a syntactical but a semantic change...