In the Plugin Manager, Available tab, I desired to look for HTTP Request. So I typed "http" and surprisingly, I got the full list of plugin. I imagine it's the commun case where the URL of the plugins is checked for inclusion, completely and not only the relevant part.
Improvement: check only the information with real value
Search for "plugin" also returns a full list - eg: "Plugin Usage" plugin. Mind you, many descriptions also start "This plugin ...". There may be other words also caught up in such results.