[moogly]

This is "built into" PowerToys Run. In fact, at the beginning that was all it could do.

It's now been moved into a bundled plugin named after the original app that was morphed into this: WindowWalker. I don't remember what the special character you have to type to target the plugin is because I made my installation of PowerToys Run use that plugin by default without a prefix and I disabled all the other plugins.

[artimaeis]

As of the version I have installed (0.58) WindowWalker is included by default in the results of the PowerToys Run results. To target windows specifically the default character is `<`.