This page is just a reference of all the known Steam APIs, I do not know how they work. Please do not email me with questions.
UNDOCUMENTEDGetPlusHeroAllyAndEnemyData
https://api.steampowered.com/IDOTA2Plus_570/GetPlusHeroAllyAndEnemyData/v1/
UNDOCUMENTEDGetPlusHeroTimedStats
https://api.steampowered.com/IDOTA2Plus_570/GetPlusHeroTimedStats/v1/
UNDOCUMENTEDGetPlusStatsData
https://api.steampowered.com/IDOTA2Plus_570/GetPlusStatsData/v1/