Adding upstream as a second remote was meant to make updates viewable as a diff. The
first measurement contradicted what this document has claimed since August: diffing
v1.12.17 against the import commit yields 783 files, 115 of which exist only on our
side and 62 only in the tag.
The telling ones are MVVM files - TextualBodyViewModel.tsx and RovingTabIndex.tsx -
absent from the v1.12.17 tag, present in v1.12.26 and present in our import. The
changelog stops at 1.12.17 because it is only written at release time. So the base is
a develop state after the 1.12.17 release, not the tag.
That matters for the plan rather than for the code: grafting onto v1.12.17 would build
every future merge on an invented ancestry. Finding the real ancestor means searching
develop history, which a shallow tag fetch cannot do.
The remote is local configuration, so the setup is written down here instead of
committed.