ACTION_BOOT_COMPLETED is one of the standard actions in Android OS that Intent defines for receiving broadcasts. It is broadcasted once after the system has finished booting.

A Gmail contextual gadget is a gadget that is triggered by clues in Gmail, such as the contents of Subject lines and email messages. For example, Gmail already provides a YouTube contextual gadget. If the body of an email contains a link to a YouTube video, a clickable thumbnail view of the video appears at the bottom of the email.

W3 Total Cache is a plugin for WordPress content management system, this plugin improves the user experience of the site by increasing website performance, reducing download times via features like content delivery network (CDN) integration.

PIT is a fast bytecode-based mutation testing system for Java.

DHTMLX Scheduler is a web-based JavaScript events calendar that provides a rich and intuitive scheduling solution similar to Microsoft Outlook Calendar, Apple's iCal, or Google Calendar

TCP and UDP client/server library for Java

Pd (aka Pure Data) is a real-time graphical programming environment for audio, video, and graphical processing.

EmberFire is the officially supported Ember JS adapter for Firebase with Ember-Data.

arguments of the maxima: given a function of some arguments, argmax stands for the values of the arguments that maximizes the function.

This is the Symfony 2.5.x specific tag. Use it in addition to the symfony2 tag if your question is specific to Symfony 2.5.x — not just 2.x.