Summary: Is the usage of the word "Friday" to refer to released/old software or requirements something widely used and if so: is there a definition and/or reasoning behind this terminology?
Longer version: At my current workplace, some formal requirements are written in the form 'High-level description of some functionality', followed by "See Friday Functionality".
From context, I understand that this requirement refers to an existing functionality in already released software (from the same company) that solves the same high-level problem. I have also heard similar usage in meetings, such as: "Friday requirements", "Friday solution" or "Friday software".
Since I haven't heard it before I have tried to search with Google and asking the persons that use this terminology in meetings to find out if this is internal jargon or something widely used and preferably get a formal definition (since it is used in requirements). My success so far has been lacking.