Hi, I would like to give a short update about what currently is happening in KDE regarding SPDX markers and REUSE. -- If this is not the right list, please tell me; but right now I assume that you are interested :)
In KDE, with 24 years of source code files in our repositories, we have collected quite a zoo of different license headers over the years that are supposed to be cleaned up. Moreover, one product that we offer explicitly for usage by developers outside the KDE community are the KDE frameworks, which is a set of libraries on top of Qt that shall simplify the life of every Qt developer (all licensed as LGPL, contrary to the most other parts of KDE which are mostly GPL).
During the last months we converted all of our KDE frameworks to REUSE compatible license information and copyright statements (at least those files that contain copyright information for now). A short status update is here: https://cordlandwehr.wordpress.com/2020/08/14/spdx-for-kf5-kf6-status-update...
During this conversion, I worked on two tools that might be also interested for people outside of KDE:
1. License-Digger: This small tool was developed to do automatic conversions of code bases to REUSE compatible license statements. Note that the approach is different to the Linux Kernel, which used two existing license detection tools, compared both results, generated a conversion table and had a script that applied these changes. My approach is to trust more in the (very intense unit tested) tool and do a direct conversion but be much more restrictive about how licenses are detected: https://invent.kde.org/sdk/licensedigger
2. Build-System-Tooling for Compatibility Testing: This is still an early version, but the idea is automatically generated unit tests for checking compatibility with outbound licenses of libraries/executables. Actually, is is meant as regressions testing that added source files do not prevent the legal distribution of a binary artifact with a specific outbound license (internally it runs "reuse spdx" and uses the generated BOM file): https://invent.kde.org/frameworks/extra-cmake-modules/-/merge_requests/21
Cheers, Andreas