This sub-package contains third-party Python packages/modules that are required for some of Astropy's core functionality. It also contains third- party JavaScript libraries used for browser-based features.

In particular, this currently includes for Python:

• ConfigObj: This provides the core config file handling for Astropy's configuration system.
• PLY: This is a parser generator providing lex/yacc-like tools in Python. It is used for Astropy's unit parsing and angle/coordinate string parsing.

Packagers preparing Astropy for inclusion in packaging frameworks have different options for how to handle these third-party extern packages, if they would prefer to use their system packages rather than the bundled versions.

It is possible to change the default urls for the remote versions of these files by using the Astropy Configuration system. The default configuration file ($HOME/.astropy/config) contains a commented section [table.jsviewer] with two items for jQuery and DataTables. It is also possible to display the default value and modify it by importing the configuration module:

In [1]: from astropy.table.jsviewer import conf

In [2]: conf.jquery_url
Out[2]: u'https://code.jquery.com/jquery-1.11.3.min.js'

In [3]: conf.jquery_url = '...'

Third-party packagers can override the defaults for these configuration items by modifying the configuration objects in astropy/table/jsviewer.py, or provide astropy config files that include the overrides appropriate for the packaged version.

To replace any of the other Python modules included in this package, simply remove them and update any imports in Astropy to import the system versions rather than the bundled copies.