To mung:

• to spoil, ruin, or destroy (often followed by up).

• Computers : to make incremental changes to (a file, system, etc.), eventually ruining or destroying the original. to modify (an e-mail address) in an easily reversible way, to avoid spam.

According to Wikipedia the term is also an acronym and it appears there is no relation to munge meaning chewing but rather to mung meaning spoil, destroy: ( see above):

to mung or munge:

• is computer jargon for a series of changes to a piece of data, which are often well defined and individually reversible, but which transform the original item into an unrecognizable form. The changes may be destructive, e.g. by corrupting a computer file, or simply concealing, e.g. changes to an email address to disguise it from spambots.

• The term was coined in 1958 in the Tech Model Railroad Club at the Massachusetts Institute of Technology. In 1960 the backronym "Mash Until No Good" was created to describe Mung, and a while after it was revised to "Mung Until No Good", making it one of the first recursive acronyms. It lived on as a recursive command in the editing language TECO.

• Usages of the term appear in munged password (a strong, secure password created through character substitution), data munging (cleaning data from one "raw" form into a structured, purged one) and address munging (disguising an e-mail address).

mung, munge:

• 1. A derogatory term meaning to imperfectly transform information. 2. A comprehensive rewrite of a routine, data structure or the whole program. This term is often confused with mung and may derive from it, or possibly vice-versa.

As Ngram shows, mung has an older history then munge. I think that the latter derives from the former.

To mung:

• to spoil, ruin, or destroy (often followed by up).

• Computers : to make incremental changes to (a file, system, etc.), eventually ruining or destroying the original. to modify (an e-mail address) in an easily reversible way, to avoid spam.

According to Wikipedia the term is also an acronym and it appears there is no relation to munge meaning chewing but rather to mung meaning spoil, destroy: ( see above):

to mung or munge:

• is computer jargon for a series of changes to a piece of data, which are often well defined and individually reversible, but which transform the original item into an unrecognizable form. The changes may be destructive, e.g. by corrupting a computer file, or simply concealing, e.g. changes to an email address to disguise it from spambots.

• The term was coined in 1958 in the Tech Model Railroad Club at the Massachusetts Institute of Technology. In 1960 the backronym "Mash Until No Good" was created to describe Mung, and a while after it was revised to "Mung Until No Good", making it one of the first recursive acronyms. It lived on as a recursive command in the editing language TECO.

• Usages of the term appear in munged password (a strong, secure password created through character substitution), data munging (cleaning data from one "raw" form into a structured, purged one) and address munging (disguising an e-mail address).

mung, munge:

• 1. A derogatory term meaning to imperfectly transform information. 2. A comprehensive rewrite of a routine, data structure or the whole program. This term is often confused with mung and may derive from it, or possibly vice-versa.