@Anomie When I open the user page in a browser it works fine:

https://he.wikipedia.org/wiki/%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9:Matanya
-> ok
https://he.wikipedia.org/wiki/User:Matanya
-> ok

The English namespace prefix works on enwiki, too. (https://en.wikipedia.org/wiki/User:Matanya)

What I don't understand is that the API requests we are making always respond with something like:

{
  "servedby": "mw1120",
  "error": {
    "code": "missingtitle",
    "info": "The page you requested doesn't exist",
    "*": "See https://he.wikipedia.org/w/api.php for API usage"
  }
}

Here are the requests equivalent to the first two links:
https://he.m.wikipedia.org/w/api.php?action=mobileview&format=json&page=%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9%3AMatanya&prop=text%7Csections%7Clanguagecount%7Cthumb%7Cimage%7Cid%7Crevision%7Cdescription%7Clastmodified%7Cnormalizedtitle%7Cdisplaytitle%7Cprotection%7Ceditable&onlyrequestedsections=1&sections=0&sectionprop=toclevel%7Cline%7Canchor&noheadings=true&thumbsize=640

https://he.m.wikipedia.org/w/api.php?action=mobileview&format=json&page=User%3AMatanya&prop=text%7Csections%7Clanguagecount%7Cthumb%7Cimage%7Cid%7Crevision%7Cdescription%7Clastmodified%7Cnormalizedtitle%7Cdisplaytitle%7Cprotection%7Ceditable&onlyrequestedsections=1&sections=0&sectionprop=toclevel%7Cline%7Canchor&noheadings=true&thumbsize=640

It seems whatever GlobalUserPage is doing to show the meta user page isn't coming through to the API. Not entirely sure how that should work.

@Matanya where do you get "this page doesn't exist"?

try with the latest alpha.

In T101407#1343679, @Matanya wrote:

try with the latest alpha.

Oops! I overlooked this bug was about the mobile app...

I don't think the apps should have to know what's going on under the hooks.
Maybe a way should be provided for API users to resolve titles to whatever global page they fall back to.

The apps use Page Content Service / Mobile-Content-Service which indeed isn't aware of the global user page. Question is... should it be aware ?

In my opinion yes. Usage of global userpages is a noticeable percentage of users, and for the App to just pretend those userpages don't exist is a bug. Not only that, but it also leads to inconsistent messaging, as in all other cases it will show the page as existing (compare eg the bottom two links on https://en.m.wikipedia.org/wiki/User:Asartea/sandbox in the app. [[User:Epicgenius]] is displayed as a blue link, while [[User:Thisisanexampleimadeuptoshowcasanissue]] is displayed as a redlink). This is confusing for users, because the app is telling them there is a page by that name, until they try and actually visit it.

In T101407#8153098, @TheDJ wrote:

The apps use Page Content Service / Mobile-Content-Service which indeed isn't aware of the global user page. Question is... should it be aware ?

What happens if you try to view the file description page for an image that exists on Commons?

In T101407#8154584, @Legoktm wrote:

What happens if you try to view the file description page for an image that exists on Commons?

Shows its from commons, and provides a link to open the commons page in your browser.

@Aklapper: If i am that smart, why would i complain

Phabricator tickets are for discussing how to get technical issues closer to resolution and for managing work. They are not a forum for "complaining". Thanks for your understanding. :)

🤣🙏🏻