I've received a handful of rejection letters from the various universities I've applied to for tenure-track positions. Most have been standard-issue form letters that say, more or less, "we've filled the position, we received many high-quality applications, thanks for applying." This doesn't say anything about your application, its relative merits, etc. It doesn't say whether yours wasn't a good fit.
Occasionally, they get more detailed, sometimes even telling you when something odd happened during the process. For instance, I got one this year saying that the funding for the position was reduced so that it went from an open-rank position to entry-level. (That I received that might mean that they assumed I wouldn't work for the cheaper price, which could have been true, but I'll never know.)
Years ago, I got one from a school in a very lovely place, who had put out a very general job description, that noted they received more than 700 applications.
Today I received one of the weirder ones. It had the usual form letter fare, but then included a final paragraph that said (to paraphrase): "Obviously, this is disappointing, but keep in mind that your achievements are abiding." What the ?
I have to assume everyone they rejected got this letter, and that it wasn't sent to some particular group of applicants who had either more extensive or more impressive CVs. I mean, I do have 40-some conference presentations, a handful of peer-reviewed publications, several book chapters, and so forth, but under contemporary standards I don't think that's a lot of accomplishment as a scholar. Plus, to me, "abiding" (that word is verbatim) suggests enduring, as though something I've done has significantly changed the philosophy world, and I know for fact this is impossible. Or at least not deliberate.