That limit is set somewhere in the kernel but it's not clear if lsof is just setting that as a maximum internally or probing somewhere - I used strace -etrace='

That limit is set somewhere in the kernel but it's not clear if lsof is just setting that as a maximum internally or probing somewhere - I used strace -etrace='!close' lsof +c 64 but I couldn't see anything related to the limit.