Thunderbird has very limited junk configuration options. Please make them available to view and adjust.
I was a big fan of the add-on "junquilla" (Add-on is not compatible) that had a "junk %" column option to choose from, that would display a numerical junk score. It also had options that allowed you to set the "junk threshold", "maximum token count" and would display "current token count", "good messages trained", "junk messages trained". It also added an "uncertain" folder where Thunderbird displays emails whose junk status is uncertain, and were good candidates to train.
Please incorporate some of the features of junquilla without having to poke around in "config" to view and change them. It would be nice to have easy access to more junk options for those who have problematic junk mail issues.
See Junquilla Documentation Below:
"Thunderbird does not provide much information about the junk/spam mail management process. JunQuilla adds a number of features that make management of junk messages easier. A percentage match column allows you to see which messages are almost junk. An extended junk status column allows you to see why messages were classified a certain way - which might be, for example, by addressbook whitelisting, manually by the user, or by the statistical filter. And an "Uncertain" search folder shows messages that you should really classify manually, which also helps to improve the accuracy of the junk classification process."