Using the RTL8723BE PCIe Wireless Network Adapter . I can See that ifconfig shows:
wlan0 Link encap:Ethernet HWaddr 48:A9:D2:55:9D:01
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
This seems to imply that the adapter is supported, however in the LibreElec utility it does not show up.
I am running x86_64 image 8.90.009