uml - Understanding why the extends arrow points in the opposite direction - Stack Overflow

In class diagrams I typically see something like ClassA extends ClassB where the arrow head points to ClassA. Example, here. This has always confused me. Why is the arrow head not pointing to ClassB?

oop - Explanation of the UML arrows - Stack Overflow

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UML of use case diagram correct? Extension or generalization? - Stack Overflow

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LibreOffice Developer's Guide: Chapter 6 - Office Development - The Document Foundation Wiki

Scribble's core document representation

Programming Concepts Manual, Volume II — VMS Software, Inc.

UML Sequence type default arrows · Issue #505 · umlet/umlet · GitHub

US7576876B2 - Relay device for relaying data from a sensing device to a computer system - Google Patents

inheritance - Inherited but exclude one use case - Stack Overflow

CS 383 Software Engineering

UML Class Diagram Arrows Guide. Brief guide for choosing right type of…, by Paul Rumyancev

A Brief Tour of Responsability Driven Design