You could try & use TenFourFox, as it does not generate the notice from google
when attempting to use it with Google Accounts, especially gmail, the others do
that are out-dated, such as older FireFox, SeaMonkey, Opera, or Safari. iCab
does not appear to always generate the unsupported status notice, if you go
into that browser menu bar settings to change its 'Browser Identity' to Safari 6...
At least TenFourFox does support Tiger 10.4.11, as well as Leopard 10.5.8.
To note: this browser does not use Flash or java, by default. For some video
there are options, one is HTML5 support from the sites you visit. Other player
items such as they are, can be read about in the TenFourFox page... see:
Here is the main page with download, and other info about TenFourFox 31.2:
http://www.floodgap.com/software/tenfourfox/ - there are two versions for G4.
The iCab browser builds have some usefulness, and there are some that can
work with vintage or obsolete operating systems. Carefully note their specs.
See iCab v. 4.9 for use with Panther 10.3.9 & Tiger 10.4.11, in 32-bit:
http://www.icab.de/dl.php - iCab puts a distracting temporary brand label up in
the browser that goes away for a time, when used as-is. Licensed, it goes away.
A recent version of 'SeaMonkey for PPC' v 2.26 for Leopard 10.5.8 exists, &
I tried it. The fans run and it works really hard and slow no matter what, for me.
So I don't recommend the latest version. The older one I like that still works,
but has no secure update, was v. 2.13 SeaMonkey for PPC. An earlier build
number was for Tiger, with v. 2.13 for PPC 10.5 Leopard.
{There are some other versions of SeaMonkey, not for PPC.}
Hopefully you can find some kind of compromise; an early Intel-based Mac
with Snow Leopard 10.6.8, rosetta, and at least 2+ GB RAM helps for a start.
Good luck & happy computing! 🙂