The Bundle Repository allows you to browse a federated collection of bundles. The user interface is search based. You can enter a category, keyword, or bundle symbolic name. If you just want to browse, feel free to enter the search button without arguments. This will list all bundles. Currently, most bundles do not properly specify a category and description. This will hopefully change over time. There is also a help page

If you want to contribute to the repository you can read the provider information. If you need to create your own repository, you can use the utility. The format of the repository files is available in OSGi RFC 112 Bundle Repository. The current repository is still in its infancy. Any help and is highly appreciated.