Filters the maximum memory limit available for administration screens.
This only applies to administrators, who may require more memory for tasks like updates. Memory limits when processing images (uploaded or edited by users of any role) are handled separately.
WP_MAX_MEMORY_LIMIT constant specifically defines the maximum memory
limit available when in the administration back end. The default is 256M
(256 megabytes of memory) or the original
memory_limit php.ini value if
this is higher.