"abctx" is an extension for Google Chrome that provides bookmarking feature. The bookmarks registered in this extension are associated to the corresponding URL patterns, and are only appearing when the current browsing URL matches the registered patterns. Typical usage of the extension is to store domain-specific bookmarks. For example, you can bookmark wiki pages on a wiki site even though the wiki system does not support bookmarking. The bookmarked wiki pages are only appearing when you are accessing the wiki site, and do not necessarily require more space on the bookmark bar.