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.
PUBLISHERPOSTItemVoteSummary
https://partner.steam-api.com/ISteamPublishedItemVoting/ItemVoteSummary/v1/
NameValueTypeRequiredDescription
uint64 Yes Steam ID of user
uint32 Yes appID of product
uint32 Yes Count of how many items we are querying
uint64[] NoThe Published File ID who's vote details are required
PUBLISHERPOSTUserVoteSummary
https://partner.steam-api.com/ISteamPublishedItemVoting/UserVoteSummary/v1/
NameValueTypeRequiredDescription
uint64 Yes Steam ID of user
uint32 Yes Count of how many items we are querying
uint64[] NoA Specific Published Item