The GPL3, for example, says:
- Conveying Verbatim Copies.
You may convey verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice; keep intact all notices stating that this License and any non-permissive terms added in accord with section 7 apply to the code; keep intact all notices of the absence of any warranty; and give all recipients a copy of this License along with the Program.
The licence goes on to say that distribution of binaries is allowed as long as they are distributed under the terms of sections 4 and 5, i.e., with a copy of the licence text.
In practice is this really necessary? On a FOSS-aficionado's computer they must have hundreds of copies of each licence, and even on a regular proprietary-filled Windows machine there are probably a dozen copies. And if I wanted to look at the licence of the GPL or MIT I wouldn't go digging for the copy that's included in the program, I'd find the text of the licence online.
This looks to me like it would be a technical violation of the licence, though it is exceedingly common. Debian packages do not include the common licences, and many npm packages don't either. So do we need to, and if we don't, would it impact the enforceability of the licence later on?