This picture shows the BibTeX completion in action. The cursor disappeared
from the screenshot, but you can see the "shadow" of it, as one
of the curly braces is highlighted on the line where the error is.
This picture shows navigation from build errors to source file. Latex
reports all kinds of warnings and errors, and not all of them contain a
line number. However, there usually is also a valid error message with
line number information.