+The main data file is varcon.txt. It contains information on the
+preferred American, British, and Canadian spelling of a word as well
+as other variant information.
+
+Each line contains a mapping between the various spellings of a word.
+Words are tageed to indicate where the spelling is used, and each
+word/tag pair is separated with a " / ". For example in the line:
+ A Cv: acknowledgment / Av B C: acknowledgement
+"acknowledgment" and "acknowledgement" are two spellings of the same
+word and "A", "Cv", "B", etc are the tags. Tags are seperated by
+spaces and the group of tags is seperated from the word with a ": ".
+Here, "acknowledgment" is the preferred American spelling (as
+indicated by the "A") of the word, and "acknowledgement" is the
+preferred Canadian and British spelling ("B" and "C"). However the
+American spelling is sometimes used in Canada (as indicated by "Cv",
+where the lowercase "v" indicated a variant form) and the British
+spelling is sometimes used in America (as indicated the the "Av").
+
+More generally each tag consists of a spelling category (for example
+"A") followed possible by a variant indicator. The spelling
+categories are as follows:
+ A: American
+ B: British "ise" spelling
+ Z: British "ize" spelling or OED prefered Spelling
+ C: Canadian
+ _: Other (Variant info based on American dictionaries, never used
+ with any of the above).
+and the variants tags are as follows:
+ .: equal
+ v: variant
+ V: seldom used variant
+ -: possible variant, should generally not used
+ x: improper variant (should not use)
+
+The "." or equal variant tags are reserved for special cases when
+there is little agreement between dictionaries or when I think the
+dictionary is wrong. The "v" indicator is used for most words marked
+as variants in the dictionary. However, some variants will be demoted
+to a "V". For example, if the variant is marked as "also" by
+Merriam-Webster, or also if only some dictionaries acknowledge the
+existence the variant. "-" is used when the variant is generally not
+listed is the dictionary but I could find some evidence of it use, or
+when it is it marked as as a archaic spelling for the word. The "x"
+is used when the spelling is almost generally considered a
+misspelling, and is only included for completeness.
+
+If there are no tags with the 'Z' spelling category on the line than
+'B' implies 'Z'. Similarly if there are no 'C' tags than 'Z' implies
+'C'.
+
+For ease of reading and maintaining the data file, each line is
+grouped in a cluster of closely related words. Each cluster is
+uniquely identifed by a headword, which is generally the American
+spelling of word on the first line of the cluster. Each cluster is
+started with a '#' and is followed by the headword with some
+additional information after it. For example the cluster for
+acknowledgment is:
+ # acknowledgment <verified> (level 35)
+ A Cv: acknowledgment / Av B C: acknowledgement
+ A Cv: acknowledgments / Av B C: acknowledgements
+ A Cv: acknowledgment's / Av B C: acknowledgement's
+The "<verified>" tag will be explained latter, and "(level 35)"
+indictated what level in SCOWL (see http://wordlist.sourceforge.net)
+the headword is found in. The levels generaly mean the following:
+ <= 35: Very common word
+ <= 70: Can be found in the dictionary
+ 80: Likely a valid word, can likely be found in an
+ unabridged dictionary
+ > 80: May not even be a legal word
+
+Sometimes the spelling of a word depends on the usage. If so the word
+is listed more than once within a cluster, with any usage information
+being indicated after a " | ". For example here is part of the cluser
+for prize:
+ A B: prize | reward
+ A B: prizes | reward
+ A C: prize / B: prise | otherwise
+ A C: prizes / B: prises | otherwise
+which indicated than the preferred spelling of prize is always with a
+"z" when meaning a reward, but otherwise is spelled with a "s" is
+British English. In the example above a brief definition of the word
+is given, but often no such attempt is made, and the definition simply
+consists of a number, for example:
+ A B: sake | :1
+ A C: sake / Av B Cv: saki | :2
+
+Sometimes part-of-speach (POS) info is given to help distinguish which
+form is used. For example:
+ A B C: practice / AV Cv: practise | <N>
+ A Cv: practice / AV B C: practise | <V>
+POS info is always given given in the form "<POS>" and if a definition
+is also given the the POS info is always first. The POS tags used are as
+follows:
+ <N>: Noun
+ <V>: Verb
+ <Adj>: Adjective
+ <Adv>: Adverb
+
+A "(-)" before the definition indicated a rarly used or archaic form
+of a word, for example:
+ A B: bark | :1
+ A: bark / Av B: barque | (-) ship
+
+A "--" indicates a note rather than definition. This is generally
+used to indicate that the spelling of the plural form not depend on
+the spelling of the root word, for example:
+ _: cabby / _.: cabbie
+ _: cabbies | -- plural
+
+Misc. notes on a particular form of a word are given after a "#" on
+the same line. Misc. notes for the cluster are given at the end of
+the cluster and are prefixed with "##", for example:
+ # coloration <verified> (level 50)
+ A B C: coloration / B. Cv: colouration
+ A B C: colorations / B. Cv: colourations
+ A B C: coloration's / B. Cv: colouration's
+ ## OED has coloration as the prefered spelling and discolouration as a
+ ## variant for British Engl or some reason
+In the notes ODE (not to be confused with OED) stands for Oxford
+Dictionary of English, "Ox" is used for any Oxford dictionary, and
+"M-W" for Merriam-Webster.
+
+Earlier versions of varcon contained numerous errors. With version
+5.0 massive effort has been made to correct many of these errors.
+Clusters that have undergone some form of verification (and likely
+correction) are marked with "<verified>". As of version 5.0, most
+clusters with headwords word in common usage (SCOWL level 35 and
+below) should now be checked, as well as many others. No effort was
+made to check clusters with headwords in SCOWL level 80 and above;
+many of those entries are unlikely to be in the dictionary anyway.