Focused crawls are collections of frequently-updated webcrawl data from narrow (as opposed to broad or wide) web crawls, often focused on a single domain or subdomain.
Two flags that exist in Hunspell's code but are unused in any dictionaries are:
NONGRAMSUGGEST: undocumented, excludes root words in the process of ngram suggestions. It's a changes of two lines in the code, but why add it when it isn't used.
SUGSWITHDOTS: it's documented but it isn't used and it is a questionable feature because it greatly depends on the segmentation of a text int
It is a spell checker implemented using bloom filters that highlights spelling mistakes. A file is taken as an input which is checked against the provided dictionary highlighting the words not present in the dictionary.
Two flags that exist in Hunspell's code but are unused in any dictionaries are: