MP3 Diags
The documentation is slightly out of date, because it still shows 1-letter labels instead of the 2-letter labels that are used now. Background colors have have been changed as well, so new screenshots are needed. However, these shouldn't matter much, so I'm postponing taking new screenshots until I'm done with the changes.
Notes about the documentation
There are enough features and options that more than 100 printed pages would be needed to describe them all in detail. Currently I have no plans to document everything, but I hope that the interface is intuitive enough to allow most users to easily figure out what can be done and how to do it, especially if they read the limited documentation that is available. However, if I receive questions about how to do one thing or another, it's quite likely that I'll add the answer to the appropriate place in the documentation.
Given that a picture is worth a thousand words, I figure that some 20 pictures with plenty of words in them should be worth a lot. So the approach to documentation is to mainly use annotated screenshots. I think it would be a good idea to look at the screenshots and read some of the text before trying to use MP3 Diags.
If you didn't already, it's probably a good idea to take a look at the MP3 introduction; while it won't turn somebody who knows nothing about MP3s into an expert (BTW, I'm not seeing myself as an MP3 expert), it puts things into MP3 Diags' perspective.
Besides being available online, the documentation can be downloaded to your computer from this link.
Contents
First run
Scanning MP3 files
Main window
Main window - Tools
Transformations - Details
Main window - All notes
Main window - Tag details
Note filter
Folder filter
Tag editor
Querying Discogs or MusicBrainz
Tag editor - Assigning images
Tag editor - Patterns
Normalization
File renamer
Config - Files
Config - Ignored notes
Config - Custom transformations
Config - Audio quality
Config - Transformation parameters
Config - Others
Advanced features