My deepest apologies if this is difficult to work with. I'm not a stata user, i'm just trying to decipher existing code

Input
year etype category value avg_freq
1996 1 1 25526966.0 8
1997 1 1 3266403.0 8
1998 1 1 1870628.0 8


Code:
import excel "\\inputdata.xlsx", firstrow case(lower)


levelsof category, l(smoothingcategory)

foreach i of local smoothingcategory {
keep if etype==1 & value != . & category==`i'

tsset year
tssmooth exponential smoothed=value, samp0(2) forecast(1)
gen parameter=r(alpha)

if (parameter > .5 & avg_freq > 50) {
drop smoothed parameter
tssmooth exponential smoothed=value, parms(.5) samp0(2) forecast(1)
gen parameter=r(alpha)
}
else if (avg_freq < 50 & parameter > .1) {
drop smoothed parameter
tssmooth exponential smoothed=value, parms(.1) samp0(2) forecast(1)
gen parameter=r(alpha)
}

replace category=`i' if missing(category)
}

Output
Can someone explain how "smoothed" and "parameter" are calculated? anyone have a formula they can share?
year etype category value avg_freq smoothed parameter
1996 1 1 25526966 8 14396684 0.0001305
1997 1 1 3266403 8 14398137 0.0001305
1998 1 1 1870628 8 14396684 0.0001305