The biggest advantage of open-source software is that developers are free to make changes to existing code and create completely customized version of the software, benefiting from the same "Project Pale Moon" is making Firefox faster by upto 25% on Windows platform by removing unwanted code (for most users) and optimizing it to benefit from latest CPU features making full use of enhanced instruction sets of newer CPUs.

To achieve it's faster Firefox build goal "Pale Moon" disables features like ActiveX and ActiveX scripting, Accessibility features, Parental controls, Javascript debugging support, crashreporter and automatic updater by design. Also, do note that since "Pale Moon Browser" is specifically optimized for current processor generation that is 7th or later generation CPU with SSE2 support the browser will not run or will have problems on older hardware configurations.