Recorder chip warning
From Halopedia, the Halo wiki
The recorder chip warning is an Easter egg in which a humorous message is found on the recorder chip from Private First Class Wallace A. Jenkins's helmet during the cutscene in 343 Guilty Spark, the 6th level of Halo: Combat Evolved. The chip has the words "DO NOT EAT", a reference to Soffish, another Bungie joke. This easter egg can also be taken as a play on words, since it is a "chip", but is not edible like its snack food brethren.
Walkthrough
Use both Flycam Program and DevTrainer when the Master Chief is holding the recording chip. Pause the game before Master Chief puts it in into his helmet and rotate the view to look at the other side. Alternatively, you can look at the bitmap in the Halo Map Tools.
