Golak

Very Good question.
I am unable to find any reference in the Guru Granth Sahib Bani.

But each organizations / Gurduara Sahib management needs funds to function, pay for expenses, like building the Gurduara Sahib, maintaining it paying for utilities, and the paying for the Bhai Sahibs salary, the Langer, and all sorts of other expenses.
Management of the organization, needs money form the Sangat that benefits from there being Gurduara Sahib in the community.
Golak is one way to collect donations without having to pass the plate to the Sangat.

Now some people say it is Guru’s Golak, may be so, but Guru never comes to pick up the money, it the management who collect the money and spend (mostly) on the Gurduara approved projects.

The practice of contributing money for such activities seems to have started from the times of Guru Sahibs. It may not have been Golak, may be just a plain cloth spread somewhere for Sangat to contribute could have served the purpose.