The reference to typically refers to a specific, widely-circulated zip archive titled DownloadAll-Khmer-Fonts-9-26-15.zip . This package was a major community effort to consolidate all known Khmer Unicode fonts into a single download for easier accessibility. Overview of the 9-26-15 Collection
Official documents became searchable and archivable through standardized encoding.
Here is your recovery plan:
To understand the value of this archive, one must understand the state of Khmer computing in September 2015: