How do I know if my Apple power adapter extension cable is original?

Perhaps to look through these search results and hope to find helpful

details toward sourced product info, that may be positive or fruitful.

https://duckduckgo.com/?q=small+logo+in+Apple+mac+power+cables+help+identify+makers&t=ftsa&ia=web

4 Easy & Efficient Ways to Spot a Fake Apple Power Adapter | Verified.org

https://www.verified.org/articles/guides/real-vs-fake-apple-power-adapters

Manage your Mac notebook computer’s battery - Apple Support

//support.apple.com/guide/mac-help/manage-your-macs-battery-mh21207/12.0/mac/12.0

About your Mac notebook computer’s power adapter - Apple Support

//support.apple.com/guide/mac-help/mac-notebook-computers-power-adapter-mchlp1778/12.0/mac/12.0

If your MagSafe cable or power adapter isn't working - Apple Support

//support.apple.com/en-us/HT203207

"If your cable or power adapter still isn’t working, you can bring it and your Mac 

laptop to an Apple Store or Apple Authorized Service Provider for evaluation."

..Should this post stick, consider my "Volunteer" time here, as evidence..

Tip: Did you purchase it directly from Apple or an Apple Authorized Reseller? If so, it would be an original Apple product; if not, then it could be a fake.

While there are several adequate and honest sites, from third-party suppliers;

also containing Apple sourced content. You may choose to look through some

of those less visited, and these may require search engines; to study and learn.

A good source of replacement cable component, chargers, and replacements

with free information on their own database, is Everymac.com. Also seek facts

from OWC macsales; and where details are available, without buying anything.

A History of Apple Cables, Interfaces & Connection Types - macsales blog

https://eshop.macsales.com/blog/76594-apple-cables-interfaces-connections/

(also 'related link' page URLs are near bottom of article)

The Everymac site includes info such as 'Instruction Manual/User Guides'

maybe something about your MacBook Pro charger might be in this?

https://everymac.com/mac-manuals/index-mac-manuals.html

Or look into OWC.com for specific model configurations & replacement parts.

Older ones show hardware update parts; and newer ones, are tamper-proof.

..You may seek details from online; but those direct site URLs are their own..

After attempts to construct and edit various replies to articles the past four

days, I'm about done with this whole experimental time wastage since 2003.

Good luck & happy trails!