MintPPC is exactly what it's name says it is: a Linux Mint derivative for PowerPC-based Macintoshes. It's goal is to provide support for PPC systems when Apple et al. have basically rendered the platform obsolete.

This is the MintPPC desktop. Anyone who has used Mint before and especially Mint with LXDE will be familiar with this. It's basically just the same as the Mint 13 MATE desktop and the prior Mint 11 desktop, just with LXDE instead.

The menu is basically the same as any LXDE-based distro would have (see Lubuntu 10.04 for an example).

Like most if not all other LXDE-based distros MintPPC uses PCManFM as the file manager.

MintPPC bundles both IceWeasel (Firefox clone) and Midori to do web browsing.
Flash support is not very good, but the question becomes not how good is Flash on a PPC, but why would you use Flash on a PPC?