I got an SDK running and compiled epubinfo.
Attached are some version.
I changed the fontsize and the dutch typo mentioned earlier.
Just pick your size and rename it to epubinfo.app.
But strange things happened, depending on the firmware.
The same epubinfo.app shows perfect on a PB623 with v.4 firmware but on a PB TL3 with v5 firmware the rectangle is moved a little down the screen (see picture).
I compiled it for v.4 using the sdk from pkbchess running in emulator:
pkgname = pbsdk
pkgver = 1.1.0-2
pkgdesc = Unoficial SDK for PocketBook devices
url =
http://pbsdk.vlasovsoft.net/