I used MenuLibre to append the EXEC path for the .desktop file of “Web” (workaround for a bug which prevents Epiphany from printing files).
This created the following .desktop file at /usr/share/applications/ org.gnome.Epiphany.desktop:
[Desktop Entry]
Type=Application
Name=Epiphany #changed the name from 'Web'
GenericName=Web Browser
Comment=Browse the web
Icon=org.gnome.Epiphany
Exec=WEBKIT_FORCE_SANDBOX=0 epiphany %U #bug workaround
Actions=new-window;Incognito;
MimeType=text/html;text/xml;application/xhtml+xml;x-scheme-handler/http;x-scheme-handler/https;multipart/related;application/x-mimearchive;message/rfc822;
Categories=GNOME;GTK;Network;WebBrowser;
Keywords=web;browser;internet;
StartupNotify=true
[Desktop Action new-window]
Name=New Window
Exec=epiphany --new-window
[Desktop Action Incognito]
Name=New Incognito Window
Exec=epiphany --incognito-mode
This made the Epiphany launcher entirely disappear from the Gnome menu.
How do I append the Exec variable in a .desktop file to get a functioning launcher?