Get the Site Home extension from Opera’s extension catalog.
Site Home is an Opera port of a Safari extension that adds a toolbar button designed to take you to the current website’s start (aka. home) page. Original Safari version by Deep Informational Technologies.
The extension will override the Open History Panel keyboard shortcut (Windows only), Control–h, for it’s own purposes. Supported on all platforms.
Run make to package it as an Opera extension and open the resulting site-home.oex file with Opera. Or drag the config.xml file on top of an Opera window to install it in developer mode.