I suspect they're just trying to stop people nicking portions of the documentation for their own nefarious purposes but no, by all measures that matter to people like us, that document is not free.
But the MAAS packages in the main repos all use the AGPL3 license:
MAAS is Copyright 2012 Canonical Ltd.
Canonical Ltd ("Canonical") distributes the MAAS source code
under the GNU Affero General Public License, version 3 ("AGPLv3").
The full text of this licence is given below.
Third-party copyright in this distribution is noted where applicable.
All rights not expressly granted are reserved.
AGPL3 is a pretty strange license if you haven't seen it before. It's just like GPL3 except for an additional clause, paraphrased on the "Why AGPL?" GNU page:
if you run the program on a server and let other users communicate with it there, your server must also allow them to download the source code corresponding to the program that it's running. If what's running there is your modified version of the program, the server's users must get the source code as you modified it.
It's undoubtedly free but while most free software licenses let you keep website modifications to yourself, this requires you make them available. That could be important. It might be too free for your purposes. It's an interesting license.
Will it always be free? Probably. Standard open-source logic applies here:
- If they own the code, they could release future versions as non-free, for-money (or otherwise) releases and stop releasing under AGPL.
- But Canonical can't stop people redistributing the current version.
- And they couldn't stop somebody continuing development and/or redistributing a fork of the current version (provided it uses another name).
Like a lot of project starters, Canonical gets extended permissions from contributors to its projects. I can't remember what the current name for this copyright agreement but it would make it extremely easy for Canonical to release closed-source versions of its products... But again, they can't stop the current versions from being [A]GPL.