Mary, if you want to read more about it in English, the linked article covers it pretty well I think. “Le point médian” itself is a typographical ‘point’, that sits in the midline position of text, distinct from a period, or full stop. 

Basically, it is one of the ways that have been suggested to modify the French language for inclusivity as the dictation is addressing. Controversial, as any change to language usually is !

https://theconversation.com/inclusivity-putting-french-language-in-mortal-danger-claims-lacademie-francaise-87408