"The last-line-minimum-deficit property specifies a length (x) for the minimum line length deficit for the last line-area of a block-area. More precisely, it specifies a constraint on the last line-area child of the last block-area L generated and returned by the formatting object, such that the inline L is either equal to the available width (w) in the inline-dimension (as the term is used in the "justify" value of "text-align"), or is less than or equal to w minus x."

Above contains 'block-area L' and 'inline L'
which is confusing.

I find the use of the word 'deficit' unclear in this context, after the description in 5.2. Seems to lack clarity in what is deficient wrt what?
From the previous description "force line justification when the line length is within a certain range. " which I find clear, perhaps justify-when-greater-than
might be clearer, since the description intimates that justification will only take place when the actual length is greater than some value?