sineemore

Там же ссылка на википедию

https://fi.wikipedia.org/wiki/17._divisioona_(jatkosota)

и вот этот самый осасто
https://fi.wikipedia.org/wiki/Kevyt_osasto_19_(jatkosota)

В английской википедии Light Detachment в аналогичных текстах.

Вот еще:
"While jaeger battalions were maybe the best known of light troops of Finnish Army, they were not the only ones. Light detachment (kevyt osasto) was a unit type created from company of cavalry, company of bicycle troops and machinegun platoon. That was the theory, in practice apparently often their both companies were issued with bicycles instead of cavalry squadron getting horses. This unit type was intended for giving each division of Finnish Army a smaller mobile formation, which could be used for purposes of vanguard, rearguard, recon, screening and as a mobile reserve. But due to acute and constant shortage of infantry during Winter War, Light Detachments often ended up being used merely as more of "additional infantry". Kevyt osasto type units existed also during early Continuation War and apparently they now got more often used for their original intended purposes. Early Continuation War light detachment contained two companies of bicycle troops (jaegers) and machinegun company - and were usually motorised, but depending area where they operated sometimes got their motor vehicles replaced with horses. Grand majority of light detachments was disestablished in year 1942 and this unit type basically disappeared at that time."

http://www.jaegerplatoon.net/FORMATIONS6.htm