Continuing https://tex.stackexchange.com/a/49453/165772 as well as doubtlessly many similar answers: in pure (La)TeX,
\leq mean exactly the same. Is there any CTAN package X that intentionally (by default) redefines one or both macros such that the output is different? If so, what is X?
I deal with legacy LaTeX code of a computer-science text in German and encouter both macros. I wonder whether the author might have meant something different in hope of using the (unknown) package X later. (Of course, the author might have been misled, similarly to Is there a difference between \ge and \geq (or equivalentely between \le and leq)? or Why does \leq show up as \le?, or wished to mislead her followers. Any of it can be the case, but we don't suppose it in this question here.)
Clarification: I'm not asking how to typeset
<= or similar. (Of course, X might redefine one of the macros this way; then it's again relevant.)