Please see this thread on the topic:

<a href="https://github.community/t/inactive-username-cant-be-claimed/189177">Inactive username can't be claimed?</a> <a class="badge-wrapper  bullet" href="/c/github-help/github-account-questions/42"><span class="badge-category-parent-bg" style="background-color: #6a737d;"></span><span class="badge-category-bg" style="background-color: #fb8532;"></span><span style="" data-drop-close="true" class="badge-category clear-badge" title="Having problems with your GitHub Account? Get Help here.">GitHub Account Questions</span></a>

Lately, I’ve been little sensitive about the usernames across the websites I hold an account and started to use the same username everywhere possible. There is this guy who is blocking the username I wanted on github, from over a decade with no public activates and repositories. To claim this username I have reached out to github support and requested to release it so that I can claim. But github support rejected my request, stating it can’t be release to me. I still don’t know why I can’t clai…