"C" yellow line feature

When I push C I get a yellow bar across the top. I want to know more about this feature. The only way I've used it before is if I have extra space in the beginning of a recording and I want to start right at the music. But I'm thinking I can do much more with this feature. I don't even know what it's called so I could look it up and read about it. Doesn't it make multiple colored bars? And can't I use it to jump around the recording in different order if I want. Say I'm finished with a recording and later I want to insert a section without disrupting all the tempo bullets under the tracks....can't I just record a new section at the end and use the "yellow bars" to make it play different sections in different orders? What's the name of this feature? Thanks!