When enabling MSTP, you define one or more MSTP regions. An MSTP region defines a logical domain where multiple spanning-tree instances (MSTIs) can be administered independently of MSTIs in other regions, setting the boundary for bridge protocol data units (BPDUs) sent by one MSTI. An MSTP region is a group of switches that is defined by three parameters:
Region name - User-defined alphanumeric name for the region.
Revision level - User-defined value that identifies the region.
Mapping table - Numerical digest of VLAN-to-instance mappings.
https://www.juniper.net/documentation/us/en/software/junos/stp-l2/topics/topic-map/spanning- tree-configuring-mstp.html

Type 2 route, MAC with IP advertisement route-Type 2 routes are per-VLAN routes, so only PEs that are part of a VNI need these routes. EVPN allows an end host's IP and MAC addresses to be advertised within the EVPN Network Layer reachability information (NLRI). This allows for control plane learning of ESI MAC addresses. Because there are many Type 2 routes, a separate route-target auto-derived per VNI helps to confine their propagation. This route type is supported by all EVPN switches and routers. Type 5 route, IP prefix Route-An IP prefix route provides encoding for inter-subnet forwarding. In the control plane, EVPN Type 5 routes are used to advertise IP prefixes for inter-subnet connectivity across data centers. To reach a tenant using connectivity provided by the EVPN Type 5 IP prefix route, data packets are sent as Layer 2 Ethernet frames encapsulated in the VXLAN header over the IP network across the data centers.