påse transcription. Valid IPA

I have used lexin as a source: http://lexin.nada.kth.se/lexin/#searchinfo=both,swe_swe,påse;

Their transcription is: [²pạ̊:se]

Is it IPA or something else? Can this transcription be of any use for Wiktionary project?

IPA it isn't because there's no å in IPA, at least AFAIK. I'd say [:] means that [å] is pronounced as "long" vowel and the little [2] probably means that the word takes [-ar] -ending in the plural.