Code

• You can report bugs/problems/criticisms in the Issues tab. It helps improving the library on the long term. If you feel familiar enough with gtk-fortran you can of course also make Pull Requests.
• If you have a Fortran compiler other than GFortran and Intel ifort/ifx, you can post in the Issues tab the specific warnings or error messages obtained when building the project with cmake -D CMAKE_BUILD_TYPE=debug -D EXCLUDE_PLPLOT=true .. and running the examples. That will help find bugs and tend toward the most standard Fortran code as possible.
• For the same reason we need people building gtk-fortran under the more OS versions possible (especially for Windows and macOS) and various architectures (32/64 bits, ARM...).

Documentation

• You can write new examples in your repositories. Make a post in the tab Discussions if you want your example to be listed in the documentation.
• You can improve the documentation by writing new tutorials: make a post in the tab Discussions about your idea. You should read the Diátaxis page about tutorials.