Pale Moon: Technical Details
So, you want more details about the browser? I'll be more than happy to
This browser aims to strike a balance between features and
speed/resource use. As
such, a choice has been made to consciously disable a few features
found in other browsers that are not commonly used by the largest group
of users. If you require any of the disabled features, then the
main-line build of Pale Moon is not for you! You may find a suitable
version on the third party contributed
builds page instead.
The Pale Moon browser has, among other things, the following features:
The following features have been disabled or removed
- Optimized for current processors.This browser
will not run on particularly old systems.
- Increased stability: experience fewer crashes.
- Support for Scalable Vector Graphics (SVG) and Canvas.
- Compatibility with many Legacy Firefox Extensions (add-ons)
although we do not provide support for this, and the capability to run
these extensions will be phased out over time.
- Support for a growing number of Pale Moon specific
- Offering low-level API access to extension developers to
truly extend browser features.
- Support for Personas ("lightweight" themes).
- Support for Complete Themes.
- CSS Downloadable Font support (including WOFF and WOFF2).
- Extended HTML5, CSS3 and advanced DOM support.
- Full and ongoing support for NPAPI plugins (Java,
- Speedy scripting and page rendering.
- Superior gradients and fonts.
- Optimized, secure networking.
- Graphical tab switching with quick-search (user-selectable).
- More customization options for navigation controls and the
tab strip than other modern browsers.
- Enhanced security indicators (padlock/styling/IDN display).
- More options for recovery (safe mode dialog with various
- Accessibility features. Most
people don't have a need for specialized accessibility features for
custom input or display devices. This cuts down on the input
complexity, and increases speed, but will, obviously, not be suitable
for people who need these features.
- Parental controls. Pale Moon aims
to be a fast browser for general use, not a "secured family browser".
The design impact of operating system integrated parental controls as
introduced in Mozilla code is significant, and has had serious
implications for building the browser. As such, parental controls have
been disabled. Extensions-based parental controls are, of course, a
just-as viable alternative (and may in many cases work better!).
- WebRTC. Apart from opening up a
whole can of worms security/privacy-wise, "Web Real Time Chat"
(comparable with Skype video calls and the likes) is not considered
useful or desired functionality for Pale Moon (both according to the
developers and the users of the browser at large). This is best left to
dedicated programs or at most a browser plug-in.
- Maintenance service. Pale Moon
does not use a Windows maintenance service and does not update silently
in the background.
- Integrated PDF reader. You are
always recommended to use a separate, up-to-date document reader for
PDF files (as an external program, not as a browser plugin) for your
own security, and to have documents displayed in their fully intended
format instead of a stripped-down display in an in-browser reader.
- Tab Groups. The Tab Group (aka
Panorama) feature has never properly matured and has not seen many
people using it. In addition, the feature is generally slow to use, not
intuitive, and puts a rather hefty load on the browser when included.
For people who still prefer to use this feature even though it has been
completely removed from the browser, an add-on
is available to replace the removed code.
- In-browser DRM.
Digital Rights Management using "black box" content-decryption modules
to serve a self-imposed DRM-encumbered media market that punishes the
wrong parties has no place in Pale Moon. If you wish to use such media,
you can use plugins with DRM features like Microsoft Silverlight.
The Pale Moon browser is specifically optimized for relatively-recent
processors and uses instructions exclusively available in more modern
(or rather: not museum-grade)
processors. This means it will not run on PCs that are particularly old
by today's standards, and is likely to display errors or refuse to
start on systems with unsupported or poorly supported CPUs. Even if you
meet the minimum CPU requirements for the browser, you should not
expect wonders from your hardware if it is dated. Modern web browsers
are very much alike full-fledged 3D games in the resources and
processing power/graphics power they require.
Requirements for the regular Pale Moon browser are, in short: a CPU with SSE2 support. This support has been
present in all mainstream CPUs since the Intel Pentium 4, and the AMD
Athlon64 processors. All multi-core processors on the market should
support this instruction set.
different is this browser from Mozilla products?
The differences are increasingly significant as
time passes. Pale Moon should be
considered a "true fork" and a totally independent product.
Moon is based on a derivative of the Gecko rendering engine (Goanna)
and builds on a hard fork of the Mozilla code (mozilla-central) called
UXP, a XUL-focused application platform that provides the underpinnings
XUL applications including Pale Moon.
This means that the core rendering functions for Pale Moon and Firefox
(and rebuilds) will be a relatively close match and that functionality
in the Gecko core code, will, as a ballpark estimate, also exist in
Pale Moon. Where specific core functions have been changed, it has been
done carefully and with due consideration to provide better performance
and efficiency while not endangering the security of the browser, and
to focus on better standards compatibility and/or more sane behavior.
Moon comes with a number of different default configuration settings
than Firefox and may behave differently when certain advanced
configuration preferences are changed.
speed boosters" and general "tweak guides" written for Firefox can
actually harm Pale Moon's speed as the
configuration defaults are made with in-depth knowledge of the browser
back-end and "a higher number" or "bigger buffer" isn't always better. You are strongly advised to always use defaults as
supplied in Pale Moon.
- Changes were made to the user interface and feature set, to
incorporate functionality and visual elements in different locations
than what was
chosen by the Mozilla team, as well as retaining or
re-introducing useful elements that were removed in Firefox, and
either removing or disabling (by default) components that would not be
used by the average user. In addition, some other user interface
changes were made to provide an as consistent and intuitive interface
as possible while still staying close to what Firefox's goals have
always been. This means the "Australis" or "Photon"
will never be used in Pale Moon.
- Pale Moon offers more configurability for features, like
additional tab preferences, preferences for image loading or tab
positions, additional security preferences, and full control over
smooth scrolling, to name a few.
- Pale Moon uses a different "Sync" client and its own server
to synchronize data between different instances of the browser. This is
not compatible with Firefox Sync as used in Firefox 29 or later.
Mozilla's change to "Firefox Accounts" is a different and less secure
approach to synchronizing data and focuses more on future commercial
endeavours and services of the Mozilla Corporation and, after careful
has been rejected for use in Pale Moon (for quite the list of reasons,
to be fair).
Moon has been tested
Pale Moon builds are tested for stability before being released by
having it used for day-to-day browsing by having an unstable
for people who like to "live on the edge" and want to help Pale Moon
development by reporting bugs in these pre-release versions. Of course,
specific functional changes are always tested when they are implemented