Update introduction to the Desktop Environments section to say several desktop environments instead of three specifically.
Add new subsection for Lumina.
There are some whitespace-only linewraps in this paragraph. The only content change is in the first and next-to-last lines. Those lines should be left too long. They can be rewrapped in a whitespace-only change.
This says "one of two methods", but does not make it clear that the two methods are described next. Also, with two ways, it is simpler to just say "...can be started by either <a> or <b>" rather than splitting them into separate paragraphs.
"Lumina can be started manually by running <command>start-lumina-desktop</command>. To start Lumina automatically when &xorg; starts, change the <literal>exec</literal> line at the end of <filename>~/.xinitrc</filename> to:" Could mention startx after that.
Really? In /etc? Or in /usr/local/etc?