1. Ano, celé HTML a CSS informace ku každému elementu v DOMe.
2. Ano, devtools
3. Ano, priklad: https://stackoverflow.com/questions/3286423/is-it-possible-to-use-any-html5-fanciness-to-export-local-storage-to-excel/3293101#3293101
hodnoty vyexportovane do Excel suboru.