Am I only one who find this is a confusing phrase

[mist998]

Routes segments with the _ prefix are considered layout-routes and will not be used when matching its child routes against the URL pathname.

Realizing from Leo's video, I feel that phrase a bit short to explain this:
although _layout_a.tsx(component) containing child_route_abc.tsx(component/child route), but when TSR internally decide which component to put into Outlet, it doesn't seek for _parent_name in path, merely child route name (or, file name) will do. Then TSR look up which parent (suppose code/file organized correctly) is to wrap that found child/route.

Routes segments with the _ prefix are considered layout-routes and is not required in the URL pathname to apply layout to (wrap) its child, TSR only match child route name as part of path-finding.