Optional
Experimental
acceptOptional
inviteIf the caller has a keypair 3pid invite, the signing URL is passed in this parameter.
Optional
viaThe server names to try and join through in addition to those that are automatically chosen. Only the first 3 are actually used in the request, to avoid HTTP 414 Request-URI Too Long responses.
When accepting an invite, whether to accept encrypted history shared by the inviter via the experimental support for MSC4268.