TenFourFox comes in different tuned versions for specific PowerPC processor families:
If you feel unsure what type of PowerPC processor your Mac has, go to the Apple menu and choose "About this Mac" and check the processor field.
On the G4 Mac open the Terminal app (in Applications -> Utilities) and type the command machine and press return. You can read more in the Wiki entry; WhichVersion.
TenFourFox is a fast, efficient Web browser always based on the current version of Firefox, but unlike the main distribution TenFourFox is compatible with OS X 10.4 and 10.5 running on PowerPC processors.
TenFourFox does support most add-ons
The add-ons it does not support are those that contain native Intel code, or, on Tiger Macs (OS X 10.4), add-ons that contain native code that requires Leopard. You can continue to use add-ons compatible with the same version of Firefox in TenFourFox in most cases.
TenFourFox no longer supports plugins or Flash
As of the previous TenFourFox 6.0, for the following reasons plugin support ships disabled. Sites will now act as if no plugins were installed at all. For details and an in-depth explanation of this policy and other workarounds, see Why aren't plugins supported in TenFourFox?. You can reenable plugins at your own risk. See the section "Reenable plugins" below
Plugins on PowerPC are of special concern because Mozilla is making updates to their plugin architecture which may require the plugins themselves to be updated, and there are certain difficult-to-correct bugs with them already on Tiger. Most importantly, Adobe Flash for PowerPC is no longer maintained and has known security risks that can crash or leak data, some sites requires versions not available on the PowerPC, and QuickTime for Leopard will lose its own support with the release of OS X Lion.
For these and other reasons, TenFourFox does not run plugins, and they cannot be enabled.