deprecated mimetype?
per rfc4329, the technical term is "unregistered media type"

https://datatracker.ietf.org/doc/html/rfc4329#section-3

related

https://stackoverflow.com/a/9664327/10440128

https://github.com/danny0838/PyWebScrapBook/issues/53

quick fix

```py
# python/Lib/mimetypes.py

class MimeTypes:
# ...
    def guess_type(self, url, strict=True):
# ...

        if ext in _types_map_default:
            # prefer the python-internal values over /etc/mime.types
            return _types_map_default[ext], encoding

        if ext in types_map:
            return types_map[ext], encoding
```

why is `application/x-javascript` returned?

on linux, mimetypes.init() loads /etc/mime.types
source:
https://mirrors.kernel.org/gentoo/distfiles/mime-types-9.tar.bz2

/etc/mime.types is sorted by alphabet, so

```
cat /etc/mime.types | grep javascript
application/javascript										js
application/x-javascript									js
```

apparently, the last entry application/x-javascript
will overwrite the previous entry application/javascript

patch

https://github.com/milahu/cpython/commit/8a50633bb1b0c3e39fbe2cd467bb34a839ad068f

As noted in Issue32462, the fact that system files take precedence over the definitions in the sodlib is a feature, so the proposed patch to reverse this behaviour cannot be applied unless it is decided to change the API in this way.  That would require a discussion on python-ideas. If you want to being it up there, and there is a decision to change the behaviour, please create a new issue.

this issue is different than Issue32462
because here, both entries are valid

```
cat /etc/mime.types | grep javascript
application/javascript        js
application/x-javascript      js
```

but the alphabetical ordering of the file
makes the last entry take precedence

python could be smarter at parsing the /etc/mime.types file
in that it could give lower precedence to the deprecated types

pseudocode:

deprecated_mimetypes = set(...) # values from rfc4329
mimetype_of_ext = dict()
# parser loop
for ...
  ext = "..."
  mimetype = "..."
  if ext in mimetype_of_ext:
    old_mimetype = mimetype_of_ext[ext]
    if old_mimetype in deprecated_mimetypes:
      mimetype_of_ext[ext] = mimetype # replace old with new
      # assume that mimetype is not deprecated
  mimetype_of_ext[ext] = mimetype

edit:

-  mimetype_of_ext[ext] = mimetype
+  else:
+    # add new entry
+    mimetype_of_ext[ext] = mimetype

Ok, I reopened this as an enhancement request for mimetypes to know about the 'deprecated' types. If you want to push it forward it might be a good idea to bring this up on python-ideas as well.

python-ideas thread
https://mail.python.org/archives/list/python-ideas@python.org/thread/V53XGQPIY7ZAISMTQHPHKGWZNSN5EXQG/