It's labelled as headphone mic terminal in yellow, (ヘッドホンマイク端子
Breakdown[ヘッドホン(Heddohon)マイク(maiku) 端子(tanshi, terminal)
3rd line: マイク付きヘッドホン, the interesting characters here are "付き", wsuki, that particular kanji means attached or attached to, making it headphone attached to mic
4th line: 接続します, if I can read that tiny char. right that's 接続 (setsuzoku, connect, link, etc)
combining the last 2 lines we get approx 'mic attached headphones will connect'
There's some misinformation either in this image (maybe outdated?) or the official statements