What does the line min := i mean?

Question

Pascal

What does the line min := i mean?

program choiсesort;
var mas: array[1..5] of integer; j, i, min, obmen, gen: integer;
begin
  randomize;
  for gen:=1 to 5 do mas[gen]:=random(1, 10);
  writeln(mas);
  
  for i:=1 to 4 do begin
    min := i; {<----- почему мы присваиваем минимуму значение i ?}
    
    for j:=i to 5 do if mas[j] < mas[min] then min:=j;
    
    if min <> i then begin
      obmen := mas[i];
      mas[i]:=mas[min];
      mas[min]:=obmen;
      writeln(mas);
    end;
  end; 
end.

Answer 1

https://ru.wikipedia.org/wiki/%D0%A1%D0%BE%D1%80%D...

Answer 2

This is someone else's code. What he wanted to do with it and how it works, no one knows. Just read the steps one by one and try to figure it out.