That's definitely a thing in Germany. Pretty much all job posts there have that.
It's there because of anti-discrimination laws. Job titles and occupations in German always have a gender associated with them (it's just the way the language is), but companies aren't allowed to discriminate. So it's shorter and easier to put (m/f) at the end rather than having to always list both gender forms of job titles every time the job title comes up.
English still has some of those gender forms for older professions. For example, there's waiter/waitress so instead of always writing "waiter/waitress" they just write "waiter" and then put (m/f) at the end to indicate that they will hire either gender.
Agreed, but adding that in Dutch a shift was even made to always designate with the male form, regardless of gender. So a "directrice" (Dutch, which would mean something like "directress" in English, a female director) then overnight became a "directeur" ("director"), with no sex change.
Myself, I saw the familiar m/f designations here, and wondered whether that is still desirable, given the emerging use of additional designations?
It's a language thing. Many languages have genders attached to nouns, and the formulation is different for males and females. So in German, for example, a job posting might be for an Engineer (Techniker (m); Technikerin (f)), but instead of saying Techniker oder Technikerin, they will just write Techniker (m/f).