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.
POSTGetApplicationLogDemand

Returns whether the server would like the user to upload logs

https://api.steampowered.com/IHelpRequestLogsService/GetApplicationLogDemand/v1/
NameValueTypeRequiredDescription
uint32 Yes
POSTUploadUserApplicationLog

User uploading application logs

https://api.steampowered.com/IHelpRequestLogsService/UploadUserApplicationLog/v1/
NameValueTypeRequiredDescription
uint32 Yes
string Yes
string Yes
string Yes
uint64 Yes