EDIT: you should only use it for your firefox, NOT for the TOR browser
For all firefox users out there, here is a collection of some useful about:config adjustments. For those who don't know what about:config is: it's like the heart of the firefox in which you can change a lot of settings which are not reachable through the normal preferences. To access it just type about:config in you address bar and read the notification which might pop up. It says that you should be careful, which is true because you can easily fuck up your whole firefox if you don't know what you're doing.
However I tested the following changes and my firefox is still working. But I'd recommend to back up you firefox folder because in case anything goes wrong you don't lose any data.
If you have more about:config tips please write them in the comments.
EDIT: if you don't want to change every value manually download the user.js file (rename it to user.js after the download). For more information and where to copy this file visit this site.
Here we go:
network.http.pipelining;true //speeds up loading of websites; can cause Problems with some websites
network.http.pipelining.ssl;true // enables pipelining only for ssl connections; avoids problems occurring with http
network.http.pipelining.maxrequests;32 // number of requests sent at once
network.http.proxy.pipelining;true // if a proxy is used
network.dns.disableIPv6;true // disables IPv6 DNS Lookups
content.notify.backoffcount;5 // limits page reloads while reciving data; speeds up the download time
browser.cache.disk.enable;false // disables caching on hardrive
browser.cache.disk_cache_ssl;false // same with ssl connections
browser.cache.memory.enable;false // same with cache in memory
browser.cache.offline.enable;false // same with offline cache
browser.download.manager.alertOnEXEOpen;true // warning when opening an exe file
browser.formfill.enable;false // disables saving of formdata
places.history.enabled;false // disables recording of visited websites
browser.safebrowsing.enabled;false // disables checking website for forgery on google; may be a security risk
browser.safebrowsing. // change variables to another database to avoid google (.enabled to true)
browser.safebrowsing.malware.enabled;false // disables malwarechecking with Google service on downloded files
browser.safebrowsing.malware. // change variable to another database in order to avoid google
browser.search.defaultenginename;"%" // name of default searchengine (must be installed)
browser.sessionhistory.max_entries;5 // history of each tab (back/forward buttons)
browser.startup.homepage;about:newtab //startpage of browser
browser.startup.page;1 // startuppage of browser (1=blank)
dom.allow_scripts_to_close_windows;false //scripts cant close windows
dom.disable_image_src_set;false // disables image manipulation by scripts
dom.disable_open_during_load;true //enables firefox built in popup blocker
dom.disablewindow* // different possibilities of scripts to modify the window
dom.event.clipboardevents.enabled;false // block website access to clipboard
dom.event.contextmenu.enabled;false // disables website control over rightclick context menu
dom.popup_allowed_events // defines javascript events that are allowed to create popups
extensions.update.enabled;true // defines if extensions are checked for updates daily or not
geo.wifi.logging.enabled;false // disables firefox logging geolocation requests
geo.wifi.uri;"" // dataprovider of geolocation feature !(default Google service)!, overwrite it with a empty string
network.cookie.alwaysAcceptSessionCookies;false // disables acceptance of session cookies
network.cookie.cookieBehavior;2 // disables cookies (0:all;1:firstparty;2:no;3:almostall)
network.cookie.lifetimePolicy;2 // cookies are deleted at the end of the session
network.dnsCacheEntries;100 // number of cached DNS entries (lower number=more requests but less data stored)
network.dnsCacheExpiration;60 /time DNS entries are cached in seconds
network.http.use-cache;false //disables caching of http requests
network.prefetch-next;false // disables automatic download of linked sites which are recommended by the website
plugin.scan.plid.all;false // disables scanning registry for plugins
security.OCSP.require;true // enables OCSP Stapling which removes the need to connect to CA servers during certificate
validation, can cause trouble with some certificates
security.tls.version. // defines minimum and maximum of allowed SSL/TLS versions (0:SSL3.0;1:TSL1.0;2:TSL1.1;3:TSL1.2)
media.peerconnection.enabled;false // VPN cannot bypassed anymore (https://www.reddit.com/r/VPN/comments/2tva1o/websites_can_now_use_webrtc_to_determine_your/)
media.peerconnection.turn.disable;true // makes sure WebRTC is really disabled
media.peerconnection.use_document_iceservers;false // makes sure WebRTC is really disabled
media.peerconnection.video.enabled;false // makes sure WebRTC is really disabled
media.peerconnection.identity.timeout;1 // makes sure WebRTC is really disabled
plugins.click_to_play;true // click-to-play for plugins
geo.enabled;false // disables geolocation API to prevent websites from getting the exact location of the computer
right click -> new -> boolean -> name: 'config.trim_on_minimize' and value: true // reduce physical memory when firefox is minimized
security.dialog_enable_delay;0 (or to another value in milliseconds) // changes the delay time for the installation dialog of a new addon
browser.zoom.siteSpecific;false // doesn't save zoom settings for specific sites
browser.urlbar.clickSelectsAll;true // to select the whole URL with a click on it
browser.download.manager.scanWhenDone;false // disable antivirus scan when download completed (can take a long time with big files)
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