Maybe rephrase this part - "It is read-only by default as this provides total immunity to corruption. Using read-write mode offers much higher write performance, but adds the possibility for stray application writes thru pointers to silently corrupt the database."

I generally do think read-write mode would offer higher write performance than read only as well :)

The context is in the sentence before your quote:

> The memory map can be used as a read-only or read-write map.

So presumably lmdb writes to the database using the `pwrite` syscall by default, but can optionally write via the mmap instead - if you are willing to accept the increased risk of accidental data corruption.