how do i make geckium have chrome's icon?

so , i just got geckium and i also have another problem , and that is , that my OS is on english , i live in a spanish speaking country but even thought firefox only shows having the english language pack , it still shows everything in spanish.
also , how do i make so geckium has 2017/ 2015 google icon? i found https://github.com/ImSwordQueen/Geckium-FF-Icon-Pack but i dont know and i dont think its safe since they are .exe
please let me know if they are safe and if theres a way to fix the language thing or change the firefox icon.

u can see my firefox is in spanish (the tabs) and the icon is firefoxes.