The preference names which Configuration Mania version 1.12.2010032801 can modify is as follows (it's very loooong!): 

keyword.enabled
keyword.URL
browser.fixup.alternate.enabled
browser.fixup.alternate.prefix
browser.fixup.alternate.suffix
browser.urlbar.clickSelectsAll
browser.urlbar.doubleClickSelectsAll
browser.urlbar.autocomplete.enabled
browser.urlbar.autoFill
browser.urlbar.filter.javascript
browser.urlbar.maxRichResults
browser.urlbar.delay
browser.blink_allowed
browser.frames.enabled
layout.frames.force_resizability
image.animation_mode
browser.enable_automatic_image_resizing
browser.display.show_image_placeholders
browser.display.force_inline_alttext
gfx.color_management.enabled
gfx.color_management.mode
gfx.downloadable_fonts.enabled
html5.enable
svg.enabled
webgl.enabled_for_all_sites
webgl.software_render
webgl.osmesalib
layout.xml.prettyprint
browser.display.use_focus_colors
browser.display.focus_background_color
browser.display.focus_text_color
browser.tabs.closeWindowWithLastTab
browser.tabs.closeButtons
browser.tabs.tabClipWidth
browser.tabs.disableBackgroundClose
browser.tabs.tabMinWidth
browser.tabs.tabMaxWidth
browser.search.openintab
browser.tabs.insertRelatedAfterCurrent
browser.tabs.loadBookmarksInBackground
browser.tabs.loadDivertedInBackground
browser.tabs.selectOwnerOnClose
browser.allTabs.previews
browser.ctrlTab.previews
browser.taskbar.previews.enable
browser.sessionstore.enabled
browser.sessionstore.interval
browser.sessionstore.max_windows_undo
browser.sessionstore.max_tabs_undo
browser.sessionstore.resume_from_crash
browser.sessionstore.privacy_level
browser.chrome.site_icons
browser.chrome.favicons
browser.download.manager.addToRecentDocs
browser.download.manager.quitBehavior
browser.download.manager.showAlertOnComplete
alerts.slideIncrement
alerts.slideIncrementTime
alerts.totalOpenTime
general.useragent.override
mozilla.widget.render-mode
gfx.font_rendering.directwrite.enabled
nglayout.initialpaint.delay
content.notify.backoffcount
content.notify.interval
content.interrupt.parsing
content.max.tokenizing.time
content.switch.threshold
browser.cache.memory.enable
browser.cache.memory.capacity
browser.cache.check_doc_frequency
config.trim_on_minimize
browser.cache.disk_cache_ssl
network.prefetch-next
browser.sessionhistory.max_total_viewers
browser.cache.disk.parent_directory
geo.enabled
network.dns.disableIPv6
network.dns.disablePrefetch
gfx.use_text_smoothing_setting
browser.xul.error_pages.enabled
view_source.editor.external
view_source.editor.path
browser.backspace_action
dom.max_script_run_time
dom.allow_scripts_to_close_windows
dom.disable_window_flip
dom.disable_window_move_resize
dom.disable_window_status_change
dom.disable_image_src_set
dom.event.contextmenu.enabled
nglayout.events.dispatchLeftClickOnly
dom.disable_window_open_feature.menubar
dom.disable_window_open_feature.resizable
dom.disable_window_open_feature.scrollbars
dom.disable_window_open_feature.toolbar
dom.disable_window_open_feature.location
dom.disable_window_open_feature.status
browser.link.open_newwindow.restriction
dom.popup_maximum
privacy.popups.disable_from_plugins
dom.popup_allowed_events
browser.download.manager.scanWhenDone
browser.download.antivirus.dontclean
browser.download.manager.alertOnEXEOpen
browser.identity.ssl_domain_display
browser.ssl_override_behavior
network.http.redirection-limit
network.enableIDN
network.IDN_show_punycode
browser.history_expire_days
browser.history_expire_sites
signon.expireMasterPassword
network.cookie.lifetime.days
security.ask_for_password
security.password_lifetime
network.http.sendRefererHeader
network.http.sendSecureXSiteReferrer
network.http.version
network.http.keep-alive
network.http.pipelining
network.http.proxy.version
network.http.proxy.keep-alive
network.http.proxy.pipelining
network.http.accept-encoding
network.http.accept.default
network.http.pipelining.maxrequests
network.http.max-connections
network.http.max-connections-per-server
network.http.max-persistent-connections-per-server
network.http.max-persistent-connections-per-proxy
mousewheel.withnokey.action
mousewheel.withnokey.numlines
mousewheel.withnokey.sysnumlines
mousewheel.withaltkey.action
mousewheel.withaltkey.numlines
mousewheel.withaltkey.sysnumlines
mousewheel.withcontrolkey.action
mousewheel.withcontrolkey.numlines
mousewheel.withcontrolkey.sysnumlines
mousewheel.withshiftkey.action
mousewheel.withshiftkey.numlines
mousewheel.withshiftkey.sysnumlines
mousewheel.horizscroll.withnokey.action
mousewheel.horizscroll.withnokey.numlines
mousewheel.horizscroll.withnokey.sysnumlines
mousewheel.horizscroll.withaltkey.action
mousewheel.horizscroll.withaltkey.numlines
mousewheel.horizscroll.withaltkey.sysnumlines
mousewheel.horizscroll.withcontrolkey.action
mousewheel.horizscroll.withcontrolkey.numlines
mousewheel.horizscroll.withcontrolkey.sysnumlines
mousewheel.horizscroll.withshiftkey.action
mousewheel.horizscroll.withshiftkey.numlines
mousewheel.horizscroll.withshiftkey.sysnumlines
browser.gesture.swipe.left
browser.gesture.swipe.right
browser.gesture.swipe.up
browser.gesture.swipe.down
browser.gesture.pinch.out
browser.gesture.pinch.in
browser.gesture.pinch.out.shift
browser.gesture.pinch.in.shift
browser.gesture.twist.right
browser.gesture.twist.left
accessibility.typeaheadfind.timeout
accessibility.typeaheadfind.enablesound
accessibility.tabfocus
ui.key.accelKey
ui.key.menuAccessKey
bidi.browser.ui
bidi.characterset
bidi.controlstextmode
bidi.direction
bidi.numeral
bidi.support
bidi.texttype
layout.scrollbar.side
general.useragent.locale
layout.spellcheckDefault
layout.enable_japanese_specific_transform
browser.preferences.instantApply
browser.preferences.animateFadeIn
clipboard.autocopy
middlemouse.paste
middlemouse.contentLoadURL
middlemouse.scrollbarPosition
ui.submenuDelay
nglayout.enable_drag_images
ui.allow_platform_file_picker
extensions.getAddons.maxResults
security.dialog_enable_delay
extensions.checkCompatibility
extensions.checkCompatibility.3.6
extensions.checkCompatibility.3.7a
extensions.checkUpdateSecurity
extensions.hideInstallButton
browser.dom.window.dump.enabled
javascript.options.strict
javascript.options.showInConsole
layout.css.report_errors
javascript.options.jit.content
javascript.options.jit.chrome
nglayout.debug.disable_xul_cache
browser.cache.disk.enable

I found that Configuration Mania can modify 205 preferences.