Yes, with BackHub you can export a GitHub wiki. In fact, a GitHub wiki is nothing more than a separate repository with markdown files containing your wiki pages. Wikis are included in the backup of your GitHub repository. You can find a list of what is included in a GitHub repository backup.
First, create a full backup of your repository. If you haven’t already, follow the instructions on how to install BackHub. Once installed, wait until the backup of your GitHub repositories is completed.
Once the backup is created, open the panel of the repository that contains the wiki you want to export. Click the button “Download Wiki”. If you have installed BackHub a while ago, you can choose from older snapshots.