Why does this need to be merged? This registry never cares about version level dependencies. And they exist everywhere, not just for meson.

Why does this need to be merged? This registry never cares about version level dependencies. And they exist everywhere, not just for meson.

This was the only way I found to get a project using manifest mode to compile, even updating libpq to the latest version, it would still use an older vcpkg-tool-meson and fail (and vcpkg-tool-meson version was not overridden anywhere, there was perhaps an older version already installed, and vcpkg would not update that, probably because it was considered acceptable)

This was the only way I found to get a project using manifest mode

Manifest mode has a very clear mode of operation. How did you get to the latest libpq?
If you rolled the builtin-baseline, libpq and vcpkg-tool-meson would move together, to what was tested together in CI.
If you used an override for libpq, you could use an override for vcpkg-tool-meson.

Clearly, version>= has the desired effect. But the vcpkg maintainers usually reject such constraints, apart from tightly coupled ports like boost-*. I do remove cruft from ports, and this might fall into this category on some days.