Manual:$wgEditPageFrameOptions

This variable determines the   header to send on pages sensitive to clickjacking attacks, such as edit pages.

This prevents those pages from being displayed in a frame or iframe.

The options are:



Do not allow framing. This is recommended for most wikis.



Allow framing by pages on the same domain. This can be used to allow framing within a trusted domain. This is insecure if there is a page on the same domain which allows framing of arbitrary URLs.



Allow all framing. This opens up the wiki to XSS attacks and thus full compromise of local user accounts. Private wikis behind a corporate firewall are especially vulnerable. This is not recommended.