Please note, this is a STATIC archive of website from 03 Nov 2016, does not collect or store any user information, there is no "phishing" involved.

Finding the right place to document bugs

Bugzilla is big. Really really big. MDN is big too. This page helps to put two big things together. It:

  • Lists Bugzilla "products" that are documented on MDN
  • Describes the components within each product (component descriptions were copied / summarized from Bugzilla)
  • Maps products and components to MDN project names (ie, "Open Web")
  • Indicates the priority for MDN documentation for products and components
  • Tries to help new contributors address documentation issues (flagged using the dev-doc-wanted keyword in Bugzilla) in MDN
  • When possible, components are linked to the appropriate area of MDN, to help you find the right place to add your documentation

Bugzilla changes over time as new products and components are added. MDN priorities change as well. If you see something wrong or missing, please add it!

Add-on SDK

The software development kit for building Firefox add-ons.

Note: At this time, the add-on SDK is not documented on MDN. This will change sometime in late 2012 or early 2013. For now, add-on SDK documentation is maintained in the add-on SDK github repository.

Component Description MDN Priority
Documentation Issues with the SDK's built-in documentation  
General Other bugs  

Firefox OS

Mozilla's mobile operating system built on web standards.

Component Description MDN Priority
Builds Device or desktop build packaging or automation Medium
Gaia (and sub-components) Firefox OS user interface and apps High
General Bugs that are not more specifically Gecko or Gaia bugs. Medium
Hardware Submit bugs to request hardware Do not document


Shared components used by Firefox and other Mozilla software, including handling of Web content (HTML, CSS, scripts, images, networking, etc.).

Note: Although listed and managed as a product, this is technically a component.

Component Description MDN Priority
Build Config Core build config issues Low
Canvas: 2D HTML5 <canvas> element, its XUL sibling, and related rendering contexts High
Canvas: WebGL WebGL canvas context High
Disability Access APIs Support for accessibility APIs on the various platforms Medium
Document Navigation "docshell"; the glue that initiates and monitors document loading and associates documents to their view for rendering Medium
DOM (and sub-components) The web Document Object Model implementation of Gecko. High
Drag and Drop Drag and drop functionality anywhere in the applications Medium
Editor Midas, Mozilla's embeddable editor. Low
Embedding (and sub-components) APIs, GRE Core, Mac, MFC Embed, Packaging Low
Event Handling Keyboard typing, mouse actions, focus changes, and other event handling High
File Handling Helper applications, and guessing Content Types when they aren't specified/known Low
Find Backend   Low
Gecko Profiler Backend to the built-in profiler Low
General Bugs in Core which do not fit into other more specific Core components Varies
Geolocation Geolocation API and framework High
GFX: Color Management qcms and other issues relating to Mozilla's color management implementation Low
Mapping of cross platform rendering interfaces to Cairo APIs
Graphics: Layers Graphics subsystem that implements hardware-accelerated (and software) composition of layers of content Medium
Graphics: Text
Text and font support in Gecko, including text shaping and font selection
Hardware Abstraction Layer (HAL) Hardware Abstraction Layer (HAL) code regardless of the backend Low
History: Global All URLs that a user has visited; history window and link coloring Medium
HTML: Form Submission HTML form submission Medium
HTML: Parser consumes content from the web, parses, validates and builds a content model (document) Low
Identity Persona / BrowserID Gecko and Firefox integration High
Image Blocking (un)blocking images from servers Low
ImageLib decodes GIF, JPEG and PNG images, and provides the decoded data to the Compositor for display Medium
Installer: XPInstall Enging bugs in the underlying cross-platform installation technology Low
Internationalization issues in supporting multiple locales High
IPC inter-process communication mechanism used to isolate plugins and content in separate processes Low
Java to XPCOM Bridge interoperability between XPCOM components and Java objects Do not document
JavaScript engine The SpiderMonkey JavaScript interpreter engine for the core JavaScript language, independent of the browser's object model Low
jemalloc malloc implementation Low
js-ctypes js-ctypes is a FFI (Foreign Function Interface) component for JS/XPCOM; this lets JavaScript code run code written in C High
Keyboard: Navigation Keyboard shortcuts, access keys/accelerators, and navigation by using the keyboard Low
Layout (and sub-categories) placement of HTML / CSS components Low
Localization internationalization Medium
mach "mach" command-line tool Low
MathML Mathematical Markup Language Low
MFBT Headers, macros, data structures, methods, and other functionality which should be available to SpiderMonkey and to all Gecko code, implemented in the mfbt/ source directory Medium
mozglue Issues in the Android glue, the custom dynamic linker or other parts of the mozglue library Low
Nanojit JIT compiler infrastructure Low
Networking (and sub-categories) Modular networking library (aka "Netlib" or "Necko") Medium
Plug-ins Core Mozilla code that supports registering and using plug-ins High
Preferences: Backend libPref, the backend library that reads, parses, and writes preferences to the user's hard disk Low
Print Preview Print Preview rendering problems Low
Printing: Output printing Low
Printing: Setup OS printing system, including cross-platform components such as the page setup dialog Low
Profile: BackEnd creation, deletion and changing of user profiles during the installation process Low
Profile: Migration conversion of profiles from previous versions Low
Profile: Roaming Profile Roaming support Low
Quicklaunch QuickLaunch installer option and preference Low
RDF Resource Description Framework: Core RDF components, including the in-memory datasource, composite datasource, RDF/XML parser, and RDF resource manager Low
Rewriting and Analysis static analysis and rewriting tools Low
Security (and sub-components) CAPS, S/MIME, etc High
Selection The user action of selecting all or part of a document and highlighting the selected content Medium
Serializers Conversion to HTML or plaintext, either during saving or during copy/paste Low
Spelling checker Spelling checker Low
SQL SQL support Medium
String Hierarchy of classes related to managing character sequences Low
Style System (CSS) Handling of CSS stylesheets and the computation of style from CSS stylesheets and HTML attributes High
SVG The implementation of Scalable Vector Graphics (SVG) Medium
Tracking Bugs used to track a group of bugs Do not document
Video / Audio HTML 5 media elements (<video> and <audio>) and the codec implementations for them (Vorbis, Theora, etc) High
Web Services Using SOAP and WSDL to call Web Services from scripts Low
WebDAV Web Distributed Authoring and Versioning protocol support Low
WebRTC (and sub-components) Bugs related to the implementation of the WebRTC (Real Time Communication) standard High
Widget (and sub-components) Cross platform widget interfaces and cross platform base implementations Medium
X-remote X-Remote Client and Server Low
XBL Extensible Binding Language, used to bind new behavior and new content to XUL and HTML elements Low
XForms XForms issues including parsing, data model, form controls, and submission Low
XML Bugs in our XML handling Low
XP Toolkit/Widgets: Menus Bugs in the cross-platform menu infrastructure Low
XP Toolkit/Widgets: XUL Bugs in the XUL language Low
XPCOM Component technology Medium
XPConnect Facilitates calling between JavaScript and XPCOM components Medium
XSLT Bugs on Mozilla's XSLT support Low
XTF eXtensible Tag Framework Low
XUL XML schema for cross-platform application programming Medium


Mozilla's web browser.

Component Description MDN Priority
Bookmarks & History Bookmarks and history Medium
Build Config Build and configuration setup Low
Developer Tools (and sub-components) Developer tools within the Firefox web browser High
Disability Access Accessibility compliance Medium
Downloads Panel Issues with the Downloads Panel Low
Extension Compatibility Version level or extension problems or Gecko problems that cause extensions not to work. High
File Handling issues dealing with helper applications and guessing Content Types when they aren't specified/known Low
General bugs in Firefox which do not fit into other more specific Firefox components Varies
Help Documentation Documentation for end users Do not document (on MDN)
Installer Application install wizard Low
Keyboard Navigation
Keyboard shortcut navigation in Firefox's user interface
Location Bar "Smart Location Bar" UI element  
Menus Firefox menus  
Microsummaries Obsolete and deprecated Low
Migration Profile Migration from other browsers  
Page Info Page Info window  
Panorama Panorama (formerly known as TabCandy)  
PDF Viewer built-in PDF viewing capabilities  
Phishing Protection Phishing protection UI and service Medium
Preferences Tools->Options UI as well as the preference defaults High
Private Browsing Private Browsing implementation Medium
RSS Discovery and Preview Discovery of RSS feeds and inline preview Low
Search Internet search from the Toolbar Search field  
Security App-level security bugs High
Session Restore Session restore functionality, including the undo close tab feature Low
Shell Integration Integration with the host desktop environment  
SocialAPI UI and platform work to integrate the social experience into Firefox High
Tabbed Browser Browser tab features or problems with the widget itself  
Theme Enhancements or changes to the default theme that ships with Firefox  
Toolbars Toolbars, toolbar customization  
Untriaged Newly filed uncategorized bugs Varies
Web Apps Web Apps integration in Firefox  
Webapp Runtime Webapp runtime (stub executable launcher, XUL shell)  
WinQual Reports WinQual crash/hang data  

Firefox for Android

The mobile version of Firefox (also known by its code name, "Fennec").

Component Description MDN Priority
Add-on Manager extensions, search plugins, and other add-ons  
Awesomescreen main user interface  
Data Providers databases and content providers that handle storage and import/export of profile data  
Download Manager user interface for downloading  
Evangelism bugs that require support from Evangelism team  
General bugs that do not fit into other categories  
Graphics, Panning and Zooming Android-specific code for fast painting, scrolling, and scaling of pages on the screen  
Keyboards and IME Android text input  
Plugins content that uses the Adobe Flash Player plug-in for Android  
Reader Mode interface for the user's Reading List  
Text Selection touch gestures and draggable handles for selecting and copying text  
Theme and Visual Design images, colors, and general look and feel  
Web Apps installing, running, and managing open web applications  

Web Apps

Web Apps are applications that run on any device, and can be distributed through any store or directly by the developer.

Component Description MDN Priority
AppsInTheCloud syncing apps between Android / Mac / Windows devices  
Dashboard view and launch currently installed apps  
Extension access and install apps  
General issues that don't fit in another category  
HTML html / javascript implementation of the web apps platform  
Infrastructure infrastructure required to support WebApps project  
Soup Android application to access, and install applications from the marketplace  


Document Tags and Contributors

 Contributors to this page: fscholz, jenzed
 Last updated by: jenzed,