The Committee's most far-reaching act was not administrative. The Sikh Rehat Maryada, the code of conduct and conventions, was drafted over many years by a committee of scholars and representatives, approved in the 1930s and 1940s and published in 1945, and it is the document most Sikh institutions treat as the standard for what a Sikh does. It covers personal discipline, the conduct of worship, the ceremonies of naming, marriage, initiation and death, the running of a gurdwara, and the authority of the Panth. It is short, it is prescriptive, and it settled a great many questions that the reform movements of the previous sixty years had opened.
The Committee also holds a custodial role over the scripture. Printing of the Guru Granth Sahib is controlled, the protocols for its transport, installation, reading and rest are set out, and there is an established procedure for the respectful retirement of damaged or worn copies. Those arrangements matter because the Guru Granth Sahib is treated as the living Guru rather than as a book about one, so its handling is a matter of religious obligation and not of library practice.
Between the code and the custody, a committee created to manage buildings ended up holding the two instruments through which Sikh practice is standardised.