This flag won a nationwide poll in 1949, but some changes were made to it afterwards, leading to the Malaysian flag we know today. The reason for these changes seems somewhat unclear, more than that the politician Onn Jaafar suggested them.
The proposal was inspired by the flag of the Malaysian state Johor:
Source: Wikipedia
Tbf as an American I’ll assume and flag using a field in the top left corner accompanied by the remainder in white and another color stripes is referencing America.
The US flag is prolific enough that even the flag of Hawaii looks somewhat American despite only having a filled field in the top left accompanied by stripes.
Ironically it was an old design for British ensigns