Many of the examples in this repo use the old way of initializing OnDiskBitmap with opened filestreams like

The ODB docs indicate that this will get removed eventually https://docs.circuitpython.org/en/latest/shared-bindings/displayio/index.html#displayio.OnDiskBitmap

Older versions of CircuitPython required a file opened in binary mode. CircuitPython 7.0 modified OnDiskBitmap so that it takes a filename instead, and opens the file internally. A future version of CircuitPython will remove the ability to pass in an opened file.

It looks like it hasn't been removed yet, but perhaps is worth considering doing for 10.x if we do still want to remove the backwards compatibility.

Either way though the code in the examples here (and any other libraries / learn projects) should get updated to use the new way.