Capitalization: This was probably planned as a temporary workaround for https://bugreports.qt.io/browse/QTBUG-51712 (P3: Somewhat important). However, there is no upstream activity. It could be changed for most platforms, but we need to catch QGtk2FileDialogHelper / QGtk3FileDialogHelper.
Length: This is related to the formats supported by GDAL. Solution would be to group by first letter, such as "Geospatial vector data A-F (.abc .csv .fmt)" etc.
There is the option to not display the extensions QFileDialog::HideNameFilterDetails. However, it needs to be verified that this works on all platforms.
(I tried to find out what is the standard on Windows, but Microsoft's Windows 10 applications are inconsistent: Notepad displays extensions, but Internet Explorer does not.)
Gimp lists only the first extensions and then prints an ellipsis. Again, I'm not sure whether we can implement this with Qt, in a cross-platform way.
Steps to reproduce
Actual behaviour
Expected behaviour
At least, no need to duplicate each extension in uppercase. Anyway all variants (e.g. .foo, .FOO, .Foo, foO, etc) are accepted.
Configuration
Mapper Version: latest master Operating System: Arch Linux