With gtumbler you can
* convert many PostScript documents to PDF at once;
* concatenate many PostScript/PDF documents;
* crop margins (MediaBox, CropBox, BleedBox, TrimBox and ArtBox);
* invoke a PDF editor/annotator such as Xournal, PDFedit, or your custom application
* much more...see blueprints for future plans

It's probably hard to tell, but the icon is indeed an upside-down T-shaped tumbler...

Note to developers: the new version will be based on python3/gtk3 and will make use of the new PyPDF2 libraries.