On MacOSX you will have Chrome directory located in Library/Application Support. Open terminal application and run next commands:

cd ~/Library/Application\ Support/Google/Chrome/Default/Platform\ Notifications/
ls -la

On Gnu/Linux (at least on Linux Mint), similarly you can find the log file(s) in /home/user/.config/google-chrome/Profile 1/Platform Notifications/ – jdmayfield

Now you will see files like this:

drwx------@  7 visi  staff   224 Jul 13 18:16 .
drwx------  75 visi  staff  2400 Jul 15 11:05 ..
-rw-------@  1 visi  staff   759 Jul 15 10:57 000003.log
-rw-------@  1 visi  staff    16 Jul 13 18:16 CURRENT
-rw-------@  1 visi  staff     0 Jul 13 18:16 LOCK
-rw-------@  1 visi  staff   147 Jul 13 18:16 LOG
-rw-------@  1 visi  staff    41 Jul 13 18:16 MANIFEST-000001

You can see the most recent one is 000003.log, so check it by next command:

tail -n 100 000003.log

And you will see last 100 items from this log. Then you can open chrome settings and disable that website notification.

Note that if you have several profiles in chrome, your path can be different, like this (Profile1 instead of Default):

cd ~/Library/Application\ Support/Google/Chrome/Profile\ 1/Platform\ Notifications/