I found this assertion failure when testing legacy/trac#30429 in linux, debug build. It happens when loading `about:tor`: `Assertion failure: foundDefaultSrc (about: page must contain a CSP including default-src), at /home/user/tor/tor-browser/dom/base/Document.cpp:5179` We should investigate this, but not sure if it's `tbb-9.0-must-nightly`.