K-Meleon vs Iridium Browser

No malware/adware toolbars/extensions can be injected. You can switch off Java, JS, Flash, popups, and Ads from the toolbar or with a hotkey.

Almost every detail can be personalized:

• skin
• buttons (icon theme and on/off state)
• toolbar placement
• menus
• number of settings and preferences
• proxies (add and switch with ease)
• locale (switch on the fly without downloads and restarts)
  etc.

Light on memory footprint: the smallest RAM amount used among all the modern browsers. Fastest application startup. Very responsive. Invaluable on the older and low-end hardware.

Has hundreds of its native extensions written on its own macrolanguage.
Supports dozens of XPI-extensions for Firefox.

• Disable "Use a web service to help resolve navigation errors"
• Disable autocomplete through prediction service when typing in Omnibox
• Always send "Do-Not-Track" header
• Network/DNS prediction is disabled by default
• Block third-party cookies by default
• Link auditing (<a ping="...">) is disabled by default
• Fetch plugins list from iridiumbrowser.de where it will be updated regularly
• Site data (cookies, local storage, etc.) is only kept until exit, by default
• Passwords are not stored by default
• Input form autofill is disabled by default
• For IPv6 probes, use a DNS root server instead of Google
• The default search provider is Qwant
• Load "about:blank" on new tabs instead of the currently set search engine and/or promotions.
• Don't report Safe Browsing overrides.
• Don't use autofill download service.
• Disable cookies for safebrowsing background requests.
• Disable the battery status API.

Due to access to the Chrome Web store.

They won't update automatically in the background.

You are in control and you can do almost anything with the code.

Provides installers and packages for the most operating systems and linux distributions.

• Increase RSA keysize to 2048 bits for self-signed certificates (used by WebRTC)
• Generate a new WebRTC identity for each connection instead of reusing identities for 30 days
• Generate a new ECDHE keypair for each WebRTC connection instead of reusing them for multiple connections
• Disable using system-provided plugins (i.e. Java, Flash, etc.)

It is fast since all background services have been disabled or removed.

• Disable background mode
• Disable EV certificates, so they are shown just like "normal" certificates
• Disable Google cloud printing
• Disable Google hot word detection
• Disable Google experiments status check
• Disable Google translation service
• Disable Google promotion fetching
• Disable Google Cloud Messaging (GCM) status check
• Disable Google Now
• Disable automatic update check
• Disable profile-import on first run

Supports all the modern web features.