I am translating character 习 using https://www.yellowbridge.com/chinese/charsearch.php and it gives 冫 as the only radical for this character although my impression is that it contains the alternative form of hook radical https://en.wikipedia.org/wiki/Radical_6 as well. Actually I checked wikipedia and some other lists of Kangxi radicals (including the lists which provide some alternatives for some radicals) and noone of these lists contain this alternative form of hook radical (with extended top line), but my character drilling set lists this alternative form (this drilling set is available in print pdf format and there is no example on the interet that is why I am not providing link here).
So, does hook character has alternative form, where to get more information about it and does 习 contain this alternative form of hook character and why online dictionaries are so silent about this important fact?
why online dictionaries are so silent about this important fact?
, you're asking the wrong questions.native language users perceive this as simple question
not at all! The average Chinese native speaker doesn't know anything more about characters than the average English speaker knows about Victorian-era literature or middle English etymology. Hopefully, most of us at Chinese SE will attempt to guide people out of mistaken notions such as this,well established lists of radical-wise explanations of individual characters
, which are unfortunately widespread (radicals have nothing to do with the function of characters). If you wish to start exploring here, check out glyph-origin.