According to the website, the crescent moon, or hilal, in the Jalur Gemilang symbolises “the religion of Islam as the official religion of the federation and the nation”.
The crescent, often paired with a star, also appears on the flags of several other nations – including Algeria, Pakistan, Tunisia, and Turkiye – which, like Malaysia, are countries with Muslim majority populations.
In the field of international humanitarian aid, we even have the International Red Cross Movement for historically Christian territories and the Red Crescent for Muslim territories.
There are Muslims who reject the crescent as an Islamic symbol. One theory is that it was actually a symbol of the pre-Islamic – and, for that matter, pre-Christian – city of Byzantium...