It’s been around for quite a while (version 21 is out) but I just came across it recently. https://www.bookstackapp.com/ is its homepage but you can grab the source over on github (link on the homepage). Why would you want to host your own wiki? Keep track of information like research or recipes or a journal or…just to be a nerd! Securely share with friends – it’s got authentication via LDAP, SAML, Google, Slack and others with multi-factor authentication on a per user basis. You can restrict registration so the only way to add a user is from an admin account and you can restrict content so the site is only available to registered users. Seriously, it looks like something worth considering.