Licensed with the SPDX expression: LGPL-2.1-or-later OR LGPL-3.0-or-later

In plain english this means anyone may use this repository under the terms of the LGPL-2.1 or any later version, or the LGPL-3.0 or any later version, or they may retain these licensing terms as is. Those who contributed to this repository must grant the necessary permissions for the LGPL-2.1 and separately for the LGPL-3.0 and whatever additional permissions are necessary for the rest of this license.

The LGPL-3.0 is explicitly specified because it contains patent licensing terms not present in the LGPL-2.1

If there is a conflict, use the terms specified by the above SPDX expression and ignore the rest of this.