One can easily do co-development of Trilinos and TriBITS and develop on TriBITS for Trilinos.
Instructions for setting up to develop on TriBITS for Trilinos and performing the development processes are given at:
The basics are that one just needs to clone the TriBITS repo under the Trilinos base repo with:
$ cd Trilinos/
$ git clone [email protected]/TriBITSPub/TriBITS.git
and the configure Trilinos with:
-DTrilinos_TRIBITS_DIR:STRING=TriBITS/tribits
Then one can make changes to TriBITS in the local TriBITS repo clone on a branch, and then submit that branch as a pull request.
But before making changes to TriBITS, please note and follow the process at Contributing to TriBITS.