When trying to view the contributions of an IP range from the mobile site (link), you get the following error:

Cannot look for contributions without a user or with a user that does not exist.

IMHO this has two problems:
1 - It's impossible to view range contribs from mobile (although that can be worked around with the desktop site)
2 - The error message is too generic and doesn't provide any help in this case

I'm unsure whether this lack of feature (1.) is already known, nor how would it take to implement it. But I guess having a more detailed message would do the trick for now.

Developer notes:

It's lack of feature, Also the MobileContributions is designed to show contributions only from single user. The UI doesn't show the contributor name next to the change, if we decide to show changes from an IP range, then the only way to find out who is the contributor is to see the change (the desktop version shows both the article and the ip).

The SpecialMobileContributions::executeWhenAvailable() does a check:

if ( $this->user && ( $this->user->idForName() || User::isIP( $par )  ) {
 // use ContribsPager to retrieve history
  return;
} 
$this->showPageNotFound();

The ContribsPager supports usernames, ips and IP ranges, if we change the if statement and add IP::isValidRange( $par )

if ( $this->user && ( $this->user->idForName() || User::isIP( $par )  || IP::isValidRange( $par ) ) ) {

it works, I checked a smoke test and it renders the page properly (but as I mentioned, only shows the list of articles without contributor IPs.

For code please check: https://github.com/wikimedia/mediawiki-extensions-MobileFrontend/blob/182535a6160afb96a95890c71e2787bcfe72584c/includes/specials/SpecialMobileContributions.php#L59)

Acceptance criteria

• change the copy on this page as suck: "Unfortunately, our default mobile site does not provide contributions for a range of IP addresses. Please enable advanced mobile contributions in your settings or view this page on a desktop computer to see the list of contributions. "

pre-deployment criteria

• Make sure AMC is out on all wikis