Using epiphany-40.3-1.fc34.x86_64 webkit2gtk3-2.34.1-1.fc34.x86_64 but also the MiniBrowser, when I try to open: https://gitlab.gnome.org/GNOME/gtk/-/tree/fd69b4174867a772984eb515099160de729a1005/gtk it takes ages, and kills one CPU, to open. Search for "gtklab" (quotes for clarity only), which takes really long time to finish (in fact, I gave up very soon and didn't wait for it to search for the result).
Unable to reproduce in Gnome Web 44.2/ WebKitGTK 2.40.1