Q: Context protocols about ngettext HOT 2 OPEN

Not sure if I got your question, but CONTEXT_GLUE has nothing to do with how you define your own contexts. You can use "Menu|Printer|" with no problem as a GetParticularString method argument.
It also has nothing to do with .PO files either, as they have a separate directive msgctxt for contexts.

The context glue just something to do with how the gettext utilities work internally with the contexts and how they load the compiled translation files (.MO files).
It is specified in the GNU MO file specifications.
But you, as an API consumer, should never worry about it. Any GNU/Gettext-compatible utility will compile a .MO file with the EOT character as a separator between the context and the message id. And NGettext will load those files regardless of what generated those files as long as it follows the standard.

from ngettext.

Well, yes, exactly, we are compiling from PO to MO files. We deploy the MO files.

We integrate NGettext to load the files.

But if I understand correctly, these two layers are, technically, separate and distinct, from a a separators integration perspective.

So in this context (pardon the verbiage confusion), we do not need to worry about it, we can use our own separators to define context from msgId? I gather, yes.

Cool! 🍻

from ngettext.