Mathematica ExtraPackage
You can easily get the path to any installed package file using FindFile
, for example:
FindFile["Notation`"]
"C:\\Program Files\\Wolfram Research\\Mathematica\\11.3\\AddOns\\Packages\\Notation\\Kernel\\init.m"
If the package isn't installed, you could search it in several places on the Internet. Don't forget about this site, old Wolfram Library Archive and also brand-new Wolfram Function Repository.
Oh ok, so after some further reading, it seems that doing:
<< Notation`
does the trick. I was trying to do something like
Needs[Utilities`Notation`]
but with no success. I am not very sure where Wolfram takes the package from though?