I have some very old software (not written by me) which comes with a license which is clearly intended as a 'we really don't care what anyone does with this any more' license.
The HI-TECH Z80 CP/M C compiler V3.09 is provided free of charge for any use, private or commercial, strictly as-is. No warranty or product support is offered or implied. You may use this software for whatever you like, providing you acknowledge that the copyright to this software remains with HI-TECH Software.
It does not explicitly mention distribution of modified versions, but does appear to imply it heavily in the last paragraph (acknowledging copyright is only meaninful if use includes redistribution, and it does not forbid modification, so the license would only cover the original code).
If this is correct it would make it pretty much equivalent to MIT or 2-clause BSD. Is it?