Does the builtin open() return a generator?

This is a question about the correct terminology used for "generators". Let's look at the file object returned by the builtin function open().

1. The builtin open() function, official documentation

In the official python documentation, then open() function is said to return a "file object" and the documentation for file object does not really say what kind of creature this is, other than it has read() and write() methods and that

File objects are also called file-like objects or streams.

‍♂️ Well that's helpful, right?

2. Words from the internet

Here are some examples where the file object returned by the open() is called a generator.

2.1. How to Use Generators and yield in Python (Realpython.com)

(emphasis mine)

open() returns a generator object that you can lazily iterate through line by line

2.2. Lazy Method for Reading Big File in Python?

(Accepted answer with 400+ score, emphasis mine)

If the file is line-based, the file object is already a lazy generator of lines:

for line in open('really_big_file.dat'):
    process_data(line)

2.3. Generators in Python — 5 Things to Know (medium.com)

(emphasis mine)

using the open() method to open the EEG file will create a file object, which functions as a generator that yields a line of data as string each time.

One can probably find easily more of such examples from everywhere on the Internet..

3. Testing if file object returned by open() is a generator

Following the How to check if an object is a generator object in python? we can form few test for the file object:

In [7]: o = open(r'C:\tmp\test.csv')

In [8]: type(o)
Out[8]: _io.TextIOWrapper

In [9]: import inspect

In [10]: inspect.isgenerator(o)
Out[10]: False

In [12]: inspect.isgeneratorfunction(o)
Out[12]: False

In [13]: import types

In [14]: isinstance(o, types.GeneratorType)
Out[14]: False

All of these tests fail, hinting that the file object returned by open() is not a generator. Still, many people tend to call it a generator.

4. Generators included – or not?

So, fellow pythonistas, is it correctly said that open() function returns a generator? And does the following

for line in open('file.csv'):
    do_something(line)

involve usage of generators?