Pale Moon has a number of additional preferences in about:config (compared to Firefox) to control Pale Moon specific features. Here's an overview and brief explanation of them:
- browser.display.ignore_accessibility_theme (true/false, v25.0.0+): Allows the user to override the use of accessibility colors in browser content (web pages).
- browser.display.standalone_images.background_color (text, v15.1+): Determines the background color for stand-alone images in hex ("#rrggbb") or named color ("red", "blue").
- browser.padlock.shown (true/false, v15.2+): Controls display of the padlock for secure sites.
- browser.padlock.style (number, v15.2+): Controls the location and style of the padlock.
- browser.padlock.urlbar_background (number, v15.2+): Controls address bar shading for secure sites.
0 = no shading, 1 = shading for secure sites, 2 = shading for secure sites + mixed mode, 3 = shading for all https sites, including broken ones.
- browser.sessionstore.exactPos (true/false, v24.2.0+): Controls whether restored windows will be placed at the exact position they were at in the last session, even if that would be (partially or completely) off-screen. (hidden pref)
- browser.tabs.resize_immediately (true/false, v24.1.2+): Controls whether tabs will immediately resize to fill the tab bar when a tab is closed.
- browser.urlbar.rss (true/false, v24.1.0+): Controls whether the web feed icon is shown in the address bar or not when feeds are available.
- lightweightThemes.animation.enabled (true/false, v24.6.0+): Controls whether animated personas (lightweight themes) are allowed.
- network.stricttransportsecurity.enabled (true/false, v25.2.0+): Controls whether HSTS (HTTP Strict Transport Security) is enabled. (hidden pref) R
- security.ssl.allow_unsafe_ocsp_response (true/false, v25.0.0+): Controls whether to ignore an expired state of stapled OCSP responses. If set to true, breaks with RFC6066 (like Firefox) and ignores the fact that stapled OCSP responses may be expired. If false (the default) aborts the connection. (hidden pref)
- spellchecker.dictionary.override (string, v25.5.0+): Sets a preferred language for choice of spellchecking dictionary, overriding document/element language if set. (hidden pref)
Details for many of these preferences can be found in the Tweak Guide.
Explanation of (hidden pref): This preference by default does not show up in about:config. To change the value of it, you will have to add a new preference yourself with the exact name and type (boolean for "true/false", Integer for "number", and string for string) indicated.
Explanation of R: This preference, when changed, requires you to completely exit (Pale Moon Button -> Exit or File -> Exit) and restart the browser to come into effect.