But, I should point out: Someone can acknowledge that something is not designed or intended for a certain purpose but then recognize that despite this, it is perfectly suitable for it. i.e. a butter knife is neither designed nor intended for opening paint cans, but it's perfectly suitable for the task (at least some are).
Moreover, as software is not often stationary these days, what something is designed or intended for changes over time. Does this clause mean that no patches which intend to make the software explicitly usable in the context of a nuclear facility will ever be accepted? Does everyone sign a document saying: "While writing this patch, I made sure that I didn't accidentally think about nuclear facilities and how this patch may make the software more useful in those contexts." ?
> GPL licensing exception
If you instead replaced "exception" with a warranty disclaimer then your intent would've been more clear in your original post.
Well actually, 2 more things: distribute the modifications as well, and to use it without restrictions (Well that, plus making sure anybody who gets a copy gets the same rights).
The latter of the two points happens to be the retroactively added freedom #0 in the FSF's definition of free software[0], which is also repeated in the GPL license text, IIRC somewhere at the top. The Open Source Definition used by the OSI has clauses to a similar effect (See points 5 and 6)[1].
GP's suggestion, adding restrictions on how the software could be used, would run counter to that, conflicting with the very philosophy from which the GPL originates.
Bruce Perens, who originally wrote the Debian Free Software Guidelines[4] (the OSI OSD is based on that), also commented on that in 2019, when the idea to put forward to add ethics based usage restrictions to software licenses[2][3].
[0] https://www.gnu.org/philosophy/free-sw.en.html
[1] https://opensource.org/osd
[2] https://perens.com/2019/09/23/sorry-ms-ehmke-the-hippocratic...
[3] https://perens.com/2019/10/12/invasion-of-the-ethical-licens...
[4] https://en.wikipedia.org/wiki/Debian_Free_Software_Guideline...
Therefore any term saying
"You acknowledge that the Program is not designed or intended for use in the design, construction, operation or maintenance of any nuclear facility"
Would be completely meaningless as you wouldn't have to agree to it to run the software.