keywords are a couple of words that are relevant to the content of your page.
They are added to the generated HTML page.
It was requested for SEO purpose but they have really little effect as they were used to cheat. Google does not look at them at all.
You can also use them as variable in your page.
You can update them with the metadata manager.
By default, ComboStrap will add all the words found in the name of the page and if its parent expected the website home page.