Any convenient descriptive word or phrase, describing the
extent of the variation (e.g. word, phrase,
punctuation, etc.) its text-critical significance (e.g.
significant, accidental, unclear), or the nature
of the variation or the principles required to understand it (e.g.
lectio difficilior, usus auctoris, etc.)
from
identifies the beginning of the lemma in the base text, if
necessary.
This attribute is only used when the double-end point
method of apparatus markup is used, with the encoded apparatus held
in a separate file rather than being embedded in-line in
the base-text file.
loc
(location) indicates the location of the variation, when the
location-referenced method of apparatus markup is used.