Why mt7613 is loading "mt7663pr2h_rebb.bin"?

Device Archer C6 v3.2, running OpenWRT Snapshot r17652-21c7a8593d.

I've noticed the following message from dmesg:

[   48.309332] kmodloader: done loading kernel modules from /etc/modules.d/*
[   50.120385] mt7615e 0000:02:00.0: mediatek/mt7663pr2h.bin not found, switching to mediatek/mt7663pr2h_rebb.bin
[   50.272131] mt7615e 0000:02:00.0: HW/SW Version: 0x65322d31, Build Time: 19091404338b809
[   50.272131]
[   50.440344] mt7615e 0000:02:00.0: N9 Firmware Version: 7663mp1827, Build Time: 20190914043434

Why mt7615e driver is loading "mediatek/mt7663pr2h_rebb.bin"?

Shouldn't it be loading "mt7615_n9.bin"?

I've tried removing " kmod-mt7663-firmware-ap" but then the 5Ghz does not work anymore.

OK, I've found the following reference which may provide some additional insight to my question: