It means that there is a notice at the beginning of this website, that details how the 'Complete Control Program' (CCP) - the software you need to program the MX-880 (and all the other CCP remotes) - is NOT given out to end users by URC. It is available to download on the dealer website and if you are not a dealer, you won't have access to that.

Typically you would get the software from the dealer you purchased the remote from (they are allowed to do that). So if you bought the remote from a place that didn't (or wouldn't) supply you with the software... I'm truly sorry for you.

There are some places you can get the software from. I have heard about some people being able to download it from bit-torrent sites. I have no idea where these sites are. The file size is over 800MB.

Honestly I don't understand why URC just doesn't allow people to download it, since they allow the remotes in that series to be sold online by everybody and their mother, for near dealer cost anyway. Warning that the remotes don't come with a warranty does no good, when they are allowing it to happen so brazenly.
URC is only making themselves look bad. Indeed, reading general reviews online for the last several years, you would think URC was the devil.
Just stupid decision making at URC from the top down. On what otherwise are fabulous remotes... well maybe not the 880 but certainly many of their other remotes.