devdocs: Cron documentation example contains files which I don't have

This page:

https://github.com/magento/devdocs/blob/develop/guides/v2.0/config-guide/cli/config-cli-subcommands-cron.md

contains instructions that don’t work for me. There are three lines in the example:

* * * * * /usr/bin/php /var/www/magento2/bin/magento cron:run | grep -v "Ran jobs by schedule" >> /var/www/magento2/var/log/magento.cron.log
* * * * * /usr/bin/php /var/www/magento2/update/cron.php >> /var/www/magento2/var/log/update.cron.log
* * * * * /usr/bin/php /var/www/magento2/bin/magento setup:cron:run >> /var/www/magento2/var/log/setup.cron.log

However, for the second line, I don’t have a directory {magento2_root}/update. And for the third line, when I run that, in the log I get setup-cron.ERROR: Could not locate magento/magento2-base/composer.json file.

As my installation method I cloned the Magento2 repository and ran the installer. Is this why the regular instructions don’t apply to me? Should this case be added to the documentation?