Package is present in EPEL-7, but missing in EPEL-8
FEDORA-EPEL-2019-5e023f9e8e has been submitted as an update to Fedora EPEL 8. https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2019-5e023f9e8e
mbuffer-20190725-1.el8 has been pushed to the Fedora EPEL 8 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2019-5e023f9e8e
mbuffer-20190725-1.el8 has been pushed to the Fedora EPEL 8 stable repository. If problems still persist, please make note of it in this bug report.