Many languages distinguish between inclusive and exclusive first-person plural pronouns (“we”). The inclusive “we” specifically includes the addressee (“you and I and possibly others”), while the exclusive “we” specifically excludes the addressee (“he/she/they and I, but not you”). This grammatical distinction is called “clusivity.” While Semitic languages such as Hebrew or most Indo-European languages such as Greek or English do not make that distinction, translators of languages with that distinction have to make a choice every time they encounter “we” or a form thereof (in English: “we,” “our,” or “us”).
For this verse, translators typically select the inclusive form (including Jesus).
Source: Velma Pickett and Florence Cowan in Notes on Translation January 1962, p. 1ff.
Following are a number of back-translations of John 8:5:
Uma: “In the Law of Musa, there is a command that says: a woman who acts like that must be stoned until she is dead. So, you(s), what is your (s) judgment?'” (Source: Uma Back Translation)
Yakan: “Na, in the law that Musa left with us (incl.), the judgment of women like this one is, they should be thrown on with stones until they die. Na, as for you, what do you say?'” (Source: Yakan Back Translation)
Western Bukidnon Manobo: “And according to Moses’ law to us long ago, she must be killed by throwing stones at her. And what is your judgment on this?'” (Source: Western Bukidnon Manobo Back Translation)
Kankanaey: “Moses’ law says that a woman like this must be stoned until she dies. Now as for you (singular), what do you (singular) say?'” (Source: Kankanaey Back Translation)
Tagbanwa: “Well, since it was commanded by Moises in the laws to stone with rocks till they die those who do like she here has done, well now, what do you say?'” (Source: Tagbanwa Back Translation)
Tenango Otomi: “In the law Moses wrote it says a woman like this is to be killed by stoning. How about you, what do you say about this matter?'” (Source: Tenango Otomi Back Translation)
The name that is transliterated as “Moses” in English is signed in Spanish Sign Language in accordance with the depiction of Moses in the famous statue by Michelangelo (see here). (Source: John Elwode in The Bible Translator 2008, p. 78ff.)
Another depiction in Spanish Sign Language (source: Carlos Moreno Sastre):
The horns that are visible in Michelangelo’s statue are based on a passage in the Latin Vulgate translation (and many Catholic Bible translations that were translated through the 1950ies with that version as the source text). Jerome, the translator, had worked from a Hebrew text without the niqquds, the diacritical marks that signify the vowels in Hebrew and had interpreted the term קרו (k-r-n) in Exodus 34:29 as קֶ֫רֶן — keren “horned,” rather than קָרַו — karan “radiance” (describing the radiance of Moses’ head as he descends from Mount Sinai).
Even at the time of his translation, Jerome likely was not the only one making that decision as this recent article alludes to.