This GitHub repository is now "Old mirror of Alfresco Community Edition from before the migration to Git"
"Code is being brought from SVN into GitHub in multiple repositories", so, where is GIT repository for the Remote API project?
Do you really need the git repo? You can just look at the subversion repo. The remote-api source is under "projects", which is alfresco-open-mirror - Revision 138031: /alfresco/COMMUNITYTAGS/5.2.d/root/projects for 5.2.d, for example.
The SVN repository that Jeff mentioned is currently the official "source" to use.
The statement "Code is being brought from SVN into GitHub in multiple repositories" should be indicative enough of an ongoing process, which entails separating the projects out of a monolithic structure, migrating/cleaning up their history (in some cases maybe dropping that) and figuring out a framework to manage the public code, private code (including Enterprise Edition specific maintenance branches for otherwise public code) and a (hopefully) improved community contribution process. Obviously this cannot be done over night and Alfresco also has to divide its attention among all the ongoing support / preparation for the next version.
Use the SVN for now, and keep checking on this platform for any future announcements from Alfresco regarding changes to source access and contribution processes. You can always check the Source Code document to see which projects are already available in GitHub / GitLab.
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