...has links to downloadable documentation for Intel Parallel Studio XE 2018, but the links are broken (as are a lot of links on the Intel website).
Is there another source?
I suggest you try the latest Fortran compiler release. It implements new compiler standards and fixes bugs and security issues. And the thing I like best is there is no license manager!!
ifort (the Classic compiler) and ifx (the next generation Intel Fortran compiler) are part of the oneAPI HPC Toolkit. Or, if you just want the Fortran compilers and don't need the analyzers, for example, see this posting from Ron Green.