People wear name tags so others know their names. It only makes sense that pronoun tags are a thing as well.
At a Google Next cloud computing conference, journalist Nicole Henderson noticed a sign that said, "We care about your pronouns," offering attendees the option to add a sticker containing one of four options to their attendance badge. Two options, "He/Him" and "She/Her," are pretty standard. The other two options, "They/Them" and "Xe/Hir," are pronoun sets sometimes used by nonbinary individuals, or people who don't fit neatly into the categories of male or female.
And, apparently, this isn't a new thing — not even for Google, which offered attendees at its IO conference earlier this year the same option.