There are two totally different websites offering Lubuntu:
What is their difference?
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The official Lubuntu home is: https://lubuntu.me
If you query whois you see that lubuntu.me is registered by Canonical:
$ whois lubuntu.me [..] Registrant Organization: Canonical, Ltd. [..]
Also, some Canonical owned pages about Lubuntu stuff link to lubuntu.me:
Last, but not least the Lubuntu Wikipedia page links to lubuntu.me as the official website: https://en.wikipedia.org/wiki/Lubuntu
lubuntu.net is still around and apparently was maintained by a member of the lubuntu project. Since 2016, there seems to be some kind of beef going between the people then controlling lubuntu.net and the current lubuntu development team controlling lubuntu.me:
Because Lubuntu was founded by Mario Behling and has been grown for many years by Julien Lavergne their web site still exists. The official Canonical website is https://lubuntu.me and theirs is https://Lubuntu.net There are those of us that used Lubuntu before it became officially recognized by Canonical as an officially supported "flavor". That is why the two exist.