Collapse the pairs in your client

4 documents, 2 pages

As returned

ax_pathax_locator
Engineering Handbook a1b2c3d4e5f60718293a4b5c6d7e8f90.mdfile
Engineering Handbook a1b2c3d4e5f60718293a4b5c6d7e8f90.mds0
Engineering Handbook .../Runbooks a1b2c3d4e5f60718293a4b5c6d7e8f90.mdfile
Engineering Handbook .../Runbooks a1b2c3d4e5f60718293a4b5c6d7e8f90.mds0

Sorted on ax_path, then ax_locator, so each pair sits together.

Grouped on ax_path

pagedocuments
Engineering Handbook a1b2c3d4e5f60718293a4b5c6d7e8f90.md2
Engineering Handbook .../Runbooks a1b2c3d4e5f60718293a4b5c6d7e8f90.md2

One result per page. Both pages are real: Notion wrote the same title into a parent and a child.

The 4 Markdown documents from the match_all listing in the recorded run. Grouping happens in your client, not in the index.