Im seeing a number as shown below on my branch in GitHub desktop, here:
I do understand that if your branch is behind the remote branch you would get down array here in this section with number of commits behind etc., like this:
But what might be this #46 on my branch? My branch is up to date with remote.
On Github when you find the #
(hash), it indicates a unique reference to an issue, or a Pull Request.
If you search on remote repo the issue/pull-request number 46
probably you find the answer to your question.
In this case from the symbol of the image reported the #46
is a Pull Request and the "RED X" means that some workflow is failed.
For more detail you can visit this page.