I'm refering to the Configuration chapter (http://logback.qos.ch/manual/configuration.html)
Here are some examples:

• appender schema diagram does not include encoder.

• Text for encoder contradicts itself: "The <encoder> element takes a mandatory class attribute. . . . if the encoder class is PatternLayoutEncoder, then the class attribute can be omitted as specified by default class mapping rules." If it can be omitted then it isn't a mandatory attribute!

• The same mistake is made in the text for the layout element.

This section also leaves the reader confused about encoders vs layouts, since encodes have not yet been mentioned in the manual. The Architecture section should have already given at least basic definitions of all the entities that the configuration section is going to be working with. I'd also note that while the configuration section uses encoders in all of its examples, the log-back demo uses layouts.