Nglayout.debug.checksum xul fastload file
From MozillaZine Knowledge Base
By calculating a checksum of the FastLoad file and comparing it to past checksums, Mozilla can verify that the file hasn’t been subject to corruption or modification by an outside source. This preference determines whether Mozilla calculates a checksum on the file.
Possible values and their effects
Calculate the checksum of the FastLoad file to verify that it hasn’t change since the last time the file was written to disk. (Default)
Do not verify the FastLoad file’s checksum.
First checked in
Has an effect in