Unable to answer "What type of stile is this?" – Stile – node/13076231509 via StreetComplete 61.3:

Not sure what this type of barrier is called

Attached photo(s):
https://streetcomplete.app/p/305348.jpg

seems like there isn't a culvert here
https://www.tukwilawa.gov/wp-content/uploads/2015/11/Sensitive-Areas-Map.pdf

Is there a reason why highway=footway is used for indoor mapping here instead of highway=corridor or indoor=corridor?

This looks to have changed quite a bit with the Federal Way Link construction

Newly created sidewalks in this area (wait for updated imagery)

the official map shows more footways

spray ground 10-19:00 memorial to labor

#OsmAnd

asphalt walking trail

parade grounds amusements

concrete path