Matrix's Synapse is the reference implementation of a Matrix homeserver, written in Python. It allows users to run their own messaging server and participate in the decentralized Matrix network. Think of it as the core software that powers a Matrix server, similar to how an email server works. 

To use OpenLDAP with Matrix’s Synapse homeserver software, you can customize this YAML file to insert in the Synapse configuration file:

modules:
  - module: "ldap_auth_provider.LdapAuthProviderModule"
    config:
      enabled: true
      uri: "ldap://ldap"
      start_tls: false
      base: "ou=people,dc=example,dc=com"
      attributes:
        uid: "uid"
        mail: "mail"
        name: "cn"
        bind_dn: "uid=admin,ou=people,dc=example,dc=com"
        bind_password: "password"
        filter: "(objectClass=person)"