This summary is not the rule. The rule text controls.
Here's a plain English summary of this rule:
The prosecution and defense can agree between themselves to change how discovery works in a case, as long as the judge hasn't already made a different order and no earlier court order gets in the way. Discovery is the process where both sides share evidence and information before trial.
Both sides can agree in writing to take depositions in a flexible way. This means they can pick who runs the deposition, when and where it happens, how much notice is given, and the format used. Once they agree to these terms in writing, the deposition counts as valid and can be used in court just like any other deposition.
The two sides can also agree to change other discovery methods beyond depositions. Basically, if both the prosecution and defense agree in writing, they have some freedom to set their own ground rules for exchanging information, instead of strictly following the standard court procedures. This gives both sides flexibility to work out arrangements that fit their specific case, as long as the judge allows it.