Someone reported that the checksum verification procedure for Mac doesn't work the way it's described in the Installation Guide. Here's what they said:

I made a live-cd on OS X.
For the checksum verify, from: https://docs.fedoraproject.org/en-US/Fedora/23/html/Installation_Guide/sect-verifying-nix.html :

quote
For OSX:
$ shasum -a 256 -c *CHECKSUM
/quote

That gives on my OS X 10.11.1:
$ shasum -a 256 -c *-CHECKSUM
shasum: Fedora-Workstation-23-x86_64-CHECKSUM: no properly formatted SHA1 checksum lines found

Quick Google: https://ask.fedoraproject.org/en/question/74873/cant-verify-the-image-checksum-fedora-22/?answer=78954#post-id-78954
quote
The problem is that the format of the *-CHECKSUM file is not recognized by shasum. I solved this using the following one-liner:
$ grep '^SHA256' *-CHECKSUM | awk -F '[()=]' '{ print $4 "  " $2 }' | shasum -a 256 -c
/quote

All credit goes to user Fredy for the fix. I confirm it works.
$ grep '^SHA256' *-CHECKSUM | awk -F '[()=]' '{ print $4 "  " $2 }' | shasum -a 256 -c
shasum: Fedora-Workstation-netinst-x86_64-23.iso:
Fedora-Workstation-netinst-x86_64-23.iso: FAILED open or read
Fedora-Live-Workstation-x86_64-23-10.iso: OK
shasum: WARNING: 1 listed file could not be read

(I just had the live CD downloaded)

That's it!
Otherwise instructions are very clear on the process, I used the command line to build my USB boot stick. That step does not prevent you from installing, but having a verified checksum is always better.