Yaru MATE is the default GTK theme for Ubuntu MATE 21.04 and newer. This snap can be installed to appropriately theme snapped applications. There is a Yaru MATE icon theme snap to compliment this snap:
The packages for RHEL 8 and RHEL 7 are in each distribution’s respective Extra Packages for Enterprise Linux (EPEL) repository. The instructions for adding this repository diverge slightly between RHEL 8 and RHEL 7, which is why they’re listed separately below.
The EPEL repository can be added to RHEL 8 with the following command: