This is a way in which Selenium selects elements, this is similar to fluent API.
It makes easy for the users to read. The parameter you pass into findElement is kind of like a pseudo-selector query, like Jsoup.
For example, if you wanted to select the logo at the top right hand corner of this page, you could do
So the query By.name("q") basically selects element(s) with the attribute, name="abc"