- point to main Calamares site in the 'part of' headers instead
of to github (this is the "this file is part of Calamares"
opening line for most files).
- remove boilerplate from all source files, CMake modules and completions,
this is the 3-paragraph summary of the GPL-3.0-or-later, which has
a meaning entirely covered by the SPDX tag.
using Loader, can be reused for other widgets conversion
leave onClick example with full path, commneted out
title text for About is hardcoded, discuss option to make this configurable in welcome.conf
background color hardcoded, tested to work well in dark themes too
