I don't know what's under the hood at the moment, please just follow the example below. If you're curious, figure it out yourself and post a topic explaining the principles, thanks.
(lldb) po $x5
(lldb) memory read --size 8 --format x 0x16fd26ac8
0x16fd26ac8: 0x00000001a0d11558 0x00000000c2000000
0x16fd26ad8: 0x00000001022d4638 0x00000001037ab4f0
0x16fd26ae8: 0x0000000126f4a1c0 0x0000000126ac9ae0
0x16fd26af8: 0x00000001821e7f00 0x0000000124d31400
Note, for arm64, the 2nd command is
memory read --size 8, while for armv7/armv7s it should be
memory read --size 4.
The value you get from
0x00000001022d4638 - ASLR offset is the address of the block. Go to this address in IDA or hopper then you'll see the block implementation.