This reminds me of Perl’s esoteric $^M variable. You assign it some giant string, and in an out-of-memory condition, the value is cleared to free up some emergency space for graceful shutdown.

“To discourage casual use of this advanced feature, there is no English long name for this variable.”

But the language-build flag to enable it has a great name: -DPERL_EMERGENCY_SBRK, obviously inspired by emergency brake.