Support for Gitlab.com and other Gitlab instances is implemented in
the library glab.el. This library is build on top of ghub.el and is
maintained in the same repository, but it is distributed as a separate
package.
When accessing Gitlab.com or another Gitlab instance, use glab-request
instead of ghub-request, glab-get instead of ghub-get, etc. Likewise
use the Git variables in the gitlab group instead of those in the
github group, i.e. gitlab.user, gitlab.HOST.user and gitlab.host.
The Gitlab API cannot be used to create tokens, so Glab cannot provide a setup wizard like Ghub does. As a consequence if the user makes a request and the necessary token cannot be found, then that results in an error.
You have to manually create and store the necessary tokens. Tokens can be created at https://gitlab.com/profile/personal_access_tokens, or the equivalent URL for another Gitlab instance. To store the token locally, follow the instructions in Manually Creating and Storing a Token and How Ghub uses Auth-Source.
Packages that use Glab, can define PACKAGE-gitlab-token-scopes for
documentation purposes. But unlike PACKAGE-github-token-scopes, which
is used by the setup wizard this is optional.
And a random hint: where you would use user/repo when accessing Github,
you have to use user%2Frepo when accessing Gitlab, e.g.:
(glab-get "/projects/python-mode-devs%2Fpython-mode")