They did something similar with the Kernel in 2011. They stopped publishing the git tree for the RHEL kernel and only published the tarball with no version control. At the time, Oracle started a project to reverse engineer it back into a set of unique patchsets. Was kindof wild.
Not sure how long it lasted. It doesn't seem live now, though.
https://www.theregister.com/2011/03/04/red_hat_twarts_oracle...
https://www.theregister.com/2012/11/12/oracle_launches_redpa...