How to block extension proxy like in chrome and mozilla

[tbt_sysad]

Good day to all pfsense citizen,

im just new to PFsense. my friend recommend it to me. im using Watchguard Firebox XTM.
im interested in pfsense.

i just want to seek any help how to block extension proxy like in in chrome and mozilla,

im running my pfsense in virtualbox,

any help is very much appreciated,
thank you in advance,

tbt_sysad  :)
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"Intelligence is the ability to adapt to change."
Stephen Hawking