These filters drop IGMP/MLD packets before they enter the mesh and filter any IGMP/MLD packets coming from the mesh.
IGMP/MLD have the concept of a local, elected Querier. For more decentralization and increased robustness, the idea of this package is to split the IGMP/MLD domain a querier is responsible for, allowing to have a querier per node. The split IGMP/MLD domain will also reduce overhead for this packet type, increasing scalability.
Beware of the consequences of using this package though: You might need to explicitly, manually mark ports on snooping switches leading towards your mesh node as multicast router ports for now (Multicast Router Discovery, MRD, not implemented yet).