We intend to unship the Large-Allocation header. It was never implemented
by other browsers, nor was it standardized. It was primarily useful to get
a document in a new process on 32-bit systems so it would have sufficient
memory for certain WebAssembly or asm.js applications.
A partner we know to have used the header has indicated they no longer rely
Websites can adopt the Cross-Origin-Opener-Policy and
Cross-Origin-Embedder-Policy headers to achieve much the same effect
through the cross-origin isolated primitive.
Bug to remove: https://bugzilla.mozilla.org/show_bug.cgi?id=1598759