Before you get too excited and/or have a heart attack, this is not actual homebrew on firmware 2.7. This is a flash menu created by HellsPlumber that imitates the PSP's XMB and allows you to 'launch' flash games from this, as if you are on firmware 1.5. Here's what HellsPlumber has said about this release:
Many PSP owners enjoyed homebrew games and applications on their PSPs. But many users were either tempted into updating to play Flash or forced to update to play the latest games. I updated my PSP and after 1 week wished I hadn't.
The Flash player was a really old version so a lot of available Flash can't play, the PSP can only handle about 2mb of Flash before displaying a "not enough memory" message and because the PSP has no keyboard, most Flash games cannot be played.
This is why I made the 2.7+ Homebrew Menu. Many flash games and applications are included with this menu, ranging from Paint to Blackjack to an alarm clock . If you want to launch flash games from a PSP XMB-like interface, then this is for you!
Hellsplumber plans to add the ability to switch between themes (Cool Blue and Dark), an Internet Toolbar so your homepage can access the Homebrew Menu, and PSP Flash Radio - an Internet radio player like PSPRadio for the next release.