Hiya!
From other posts I think the response is usually if the program is not in the official repositories, it could be put in the Lite Software installer, i.e. not installed by default. Also, if a program is only in an external PPA repository, this applys too.
As for the program itself, I personnaly prefer XFCE from LL versions 4.x and up (3.8 minimum if obligated for 32bits). Previous versions give me all kinds of retro-headaches

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Cheers!