xmg:[me]:~$ pip3 show pip borgbackup pkgconfig
WARNING: Package(s) not found: borgbackup
Name: pip
Version: 21.0
Summary: The PyPA recommended tool for installing Python packages.
Home-page: https://pip.pypa.io/
Author: The pip developers
Author-email: distutils-sig@python.org
License: MIT
Location: /usr/lib/python3.10/site-packages
Requires: 
Required-by: 
---
Name: pkgconfig
Version: 1.5.5
Summary: Interface Python with pkg-config
Home-page: https://github.com/matze/pkgconfig
Author: Matthias Vogelgesang
Author-email: matthias.vogelgesang@gmail.com
License: MIT
Location: /home/me/.local/lib/python3.10/site-packages
Requires: 
Required-by:

xmg:[me]:~$ pacman -Ss pkgconfig
system/pkgconf 1.8.0-1 (base-devel)
    Package compiler and linker metadata toolkit
world/perl-extutils-pkgconfig 1.16-8
    The Perl Pkgconfig module
galaxy/perl-pkgconfig 0.25026-2
    Pure-Perl Core-Only replacement for pkg-config
galaxy/perl-pkgconfig-libpkgconf 0.11-3
    Perl bindings for libpkgconf
galaxy/python-pkgconfig 1.5.5-3
    Python module to interface with the pkg-config command line tool
galaxy/ruby-pkg-config 1.4.6-1
    Implementation of pkg-config in ruby
xmg:[me]:~$

pip3 show pip borgbackup pkgconfig
pacman -Ss pkgconfig

xmg:[me]:~$ pacman -Q
python 3.10.4-1
python-appdirs 1.4.4-6
python-cachecontrol 1:0.12.6-4
python-cairo 1.21.0-1
python-certifi 2021.10.8-3
python-cffi 1.15.0-3
python-chardet 4.0.0-5
python-colorama 0.4.4-6
python-contextlib2 0.6.0.post1-6
python-cryptography 37.0.0-1
python-distlib 0.3.4-1
python-distro 1.7.0-1
python-dnspython 1:2.2.1-1
python-gobject 3.42.1-1
python-html5lib 1.1-11
python-idna 3.3-4
python-importlib-metadata 4.8.1-3
python-markdown 3.3.7-1
python-more-itertools 8.12.0-2
python-msgpack 1.0.3-1
python-ordered-set 4.0.2-6
python-packaging 21.3-1
python-pep517 0.12.0-4
python-pexpect 4.8.0-6
python-pip 21.0-1
python-ply 3.11-10
python-progress 1.6-5
python-ptyprocess 0.7.0-4
python-pycparser 2.21-3
python-pycryptodome 3.14.1-1
python-pycups 2.0.1-5
python-pycurl 7.45.1-1
python-pyopenssl 22.0.0-1
python-pyparsing 3.0.9-1
python-requests 2.27.1-1
python-resolvelib 0.5.5-4
python-retrying 1.3.3-13
python-setuptools 1:60.6.0-1
python-six 1.16.0-5
python-toml 0.10.2-7.1
python-tomli 2.0.1-1
python-urllib3 1.26.9-1
python-webencodings 0.5.1-9

python-3.10.4-1

xmg:[me]:~$ python -m ensurepip --upgrade
Defaulting to user installation because normal site-packages is not writeable
Looking in links: /tmp/tmp3u9e68k8
Requirement already satisfied: setuptools in /usr/lib/python3.10/site-packages (60.6.0)
Requirement already satisfied: pip in /usr/lib/python3.10/site-packages (21.0)
Processing /tmp/tmp3u9e68k8/pip-22.0.4-py3-none-any.whl
Installing collected packages: pip
  WARNING: The scripts pip3 and pip3.10 are installed in '/home/me/.local/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed pip-22.0.4

xmg:[me]:~$ pip3 install pkgconfig ; pip3 install "borgbackup==1.2.0"
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: pkgconfig in ./.local/lib/python3.10/site-packages (1.5.5)
Defaulting to user installation because normal site-packages is not writeable
Collecting borgbackup==1.2.0
  Using cached borgbackup-1.2.0.tar.gz (4.0 MB)
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error
  
  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [25 lines of output]
      Traceback (most recent call last):
        File "/home/me/.local/lib/python3.10/site-packages/pkgconfig/pkgconfig.py", line 91, in _wrapper
          return func(*args, **kwargs)
        File "/home/me/.local/lib/python3.10/site-packages/pkgconfig/pkgconfig.py", line 125, in exists
          return call(cmd) == 0
        File "/usr/lib/python3.10/subprocess.py", line 345, in call
          with Popen(*popenargs, **kwargs) as p:
        File "/usr/lib/python3.10/subprocess.py", line 966, in __init__
          self._execute_child(args, executable, preexec_fn, close_fds,
        File "/usr/lib/python3.10/subprocess.py", line 1842, in _execute_child
          raise child_exception_type(errno_num, err_msg, err_filename)
      FileNotFoundError: [Errno 2] No such file or directory: 'pkg-config'
      
      During handling of the above exception, another exception occurred:
      
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 34, in <module>
        File "/tmp/pip-install-3_i6up_s/borgbackup_775a607c8c074fcb8812ace70932a084/setup.py", line 185, in <module>
          setup_crypto.crypto_ext_kwargs(pc, system_prefix_openssl),
        File "/tmp/pip-install-3_i6up_s/borgbackup_775a607c8c074fcb8812ace70932a084/setup_crypto.py", line 28, in crypto_ext_kwargs
          if pc and pc.exists('libcrypto'):
        File "/home/me/.local/lib/python3.10/site-packages/pkgconfig/pkgconfig.py", line 93, in _wrapper
          raise EnvironmentError("pkg-config probably not installed: %r" % e)
      OSError: pkg-config probably not installed: FileNotFoundError(2, 'No such file or directory')
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.
xmg:[me]:~$

pip install foo

python -V

python -m ensurepip --upgrade
pip3 install pkgconfig ; pip3 install "borgbackup==1.2.0"

pip3 show pip borgbackup pkgconfig
pacman -Ss pkgconfig