<h3 dir="auto">Bug summary</h3>
<p dir="auto">Import of matplotlib leads to <code class="notranslate">KeyError: 'webagg.port'</code> on Slackware64-current.<br>
Seems related to <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="1058947669" data-permission-text="Title is private" data-url="https://github.com/matplotlib/matplotlib/issues/21684" data-hovercard-type="pull_request" data-hovercard-url="/matplotlib/matplotlib/pull/21684/hovercard" href="https://github.com/matplotlib/matplotlib/pull/21684">#21684</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="1056948749" data-permission-text="Title is private" data-url="https://github.com/matplotlib/matplotlib/issues/21662" data-hovercard-type="pull_request" data-hovercard-url="/matplotlib/matplotlib/pull/21662/hovercard" href="https://github.com/matplotlib/matplotlib/pull/21662">#21662</a></p>
<p dir="auto">During building matplotlib from pypi.org source-tar.gz, patches corresponding to above commits had been applied, giving this<br>
matplotlibrc:</p>
<blockquote>
<p dir="auto">..<br>
## ***************************************************************************<br>
## * BACKENDS                                                                *<br>
## ***************************************************************************<br>
## The default backend.  If you omit this parameter, the first working<br>
## backend from the following list is used:<br>
##     MacOSX QtAgg Gtk4Agg Gtk3Agg TkAgg WxAgg Agg<br>
## Other choices include:<br>
##     QtCairo GTK4Cairo GTK3Cairo TkCairo WxCairo Cairo<br>
##     Qt5Agg Qt5Cairo Wx  # deprecated.<br>
##     PS PDF SVG Template<br>
## You can also deploy your own backend outside of Matplotlib by referring to<br>
## the module name (which must be in the PYTHONPATH) as 'module://my_backend'.<br>
#backend: QtAgg<br>
..</p>
</blockquote>
<p dir="auto">Still, also after commenting out <code class="notranslate">#backend: QtAgg</code> in either<br>
<code class="notranslate">~/.config/matplotlib/matplotlibrc </code><br>
or in<br>
<code class="notranslate">/usr/lib64/python3.9/site-packages/matplotlib/mpl-data/matplotlibrc</code></p>
<p dir="auto">results in this <code class="notranslate">KeyError: 'webagg.port'</code></p>
<h3 dir="auto">Code for reproduction</h3>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="bash-5.1$ python
&gt;&gt;&gt; import matplotlib"><pre class="notranslate"><span class="pl-s1">bash</span><span class="pl-c1">-</span><span class="pl-c1">5.1</span>$ <span class="pl-s1">python</span>
<span class="pl-c1">&gt;&gt;</span><span class="pl-c1">&gt;</span> <span class="pl-k">import</span> <span class="pl-s1">matplotlib</span></pre></div>
<h3 dir="auto">Actual outcome</h3>
<blockquote>
</blockquote>
<p dir="auto">bash-5.1$ python<br>
Python 3.9.9 (main, Nov 20 2021, 19:41:34)<br>
[GCC 11.2.0] on linux<br>
Type "help", "copyright", "credits" or "license" for more information.<br>
&gt;&gt;&gt; import matplotlib<br>
Traceback (most recent call last):<br>
File "", line 1, in <br>
File "/usr/lib64/python3.9/site-packages/matplotlib/<strong>init</strong>.py", line 895, in <br>
defaultParams = rcsetup.defaultParams = {<br>
File "/usr/lib64/python3.9/site-packages/matplotlib/<strong>init</strong>.py", line 898, in <br>
rcParamsDefault[key]),<br>
File "/usr/lib64/python3.9/site-packages/matplotlib/<strong>init</strong>.py", line 674, in <strong>getitem</strong><br>
return dict.<strong>getitem</strong>(self, key)<br>
KeyError: 'webagg.port'</p>
<h3 dir="auto">Expected outcome</h3>
<blockquote>
<p dir="auto">no import error, i.e:</p>
</blockquote>
<p dir="auto">bash-5.1$ python<br>
Python 3.9.9 (main, Nov 20 2021, 19:41:34)<br>
[GCC 11.2.0] on linux<br>
Type "help", "copyright", "credits" or "license" for more information.<br>
&gt;&gt;&gt; import matplotlib<br>
&gt;&gt;&gt;</p>
<h3 dir="auto">Additional information</h3>
<p dir="auto">With matplotlib-3.4.3 nothing like this.</p>
<h3 dir="auto">Operating system</h3>
<p dir="auto">Slackware64-15.0-RC2</p>
<h3 dir="auto">Matplotlib Version</h3>
<p dir="auto">3.5.0</p>
<h3 dir="auto">Matplotlib Backend</h3>
<p dir="auto">not possible</p>
<h3 dir="auto">Python version</h3>
<p dir="auto">3.9.9</p>
<h3 dir="auto">Jupyter version</h3>
<p dir="auto">not used</p>
<h3 dir="auto">Installation</h3>
<p dir="auto">from source (.tar.gz)</p>
<p dir="auto">When setting both the <code class="notranslate">markeredgecolor</code> and the <code class="notranslate">markerfacecolor</code> as a rgba tuple, the transparency of both seems to be set to the one of <code class="notranslate">markerfacecolor</code>. Could this be a bug in matplotlib or am I making a mistake?</p>
<p dir="auto">Minimal-ish example:</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import matplotlib.pyplot as plt

# plot markers with varying alpha values for edge and face colors
alpha_faces = [1.0, 0.3, 0.7, 0.3]
alpha_edges = [1.0, 0.3, 0.3, 1.0]
for n, (af, ae) in enumerate(zip(alpha_faces, alpha_edges)):
    plt.plot(n, 0, ms=20, mew=5, marker='s',  mfc=(1,0,0,af), mec=(0,0,1,ae))
    plt.text(n, 0.01, &quot;$\\alpha$ edge: {}\n$\\alpha$ face {}&quot;.format(ae, af),
            va='bottom', ha='center')

# a black line to make the transparency clearer
plt.axhline(0, color='k', lw=3, zorder=0)

plt.xlim(-0.5, n+0.5)
plt.show()"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s1">matplotlib</span>.<span class="pl-s1">pyplot</span> <span class="pl-k">as</span> <span class="pl-s1">plt</span>

<span class="pl-c"># plot markers with varying alpha values for edge and face colors</span>
<span class="pl-s1">alpha_faces</span> <span class="pl-c1">=</span> [<span class="pl-c1">1.0</span>, <span class="pl-c1">0.3</span>, <span class="pl-c1">0.7</span>, <span class="pl-c1">0.3</span>]
<span class="pl-s1">alpha_edges</span> <span class="pl-c1">=</span> [<span class="pl-c1">1.0</span>, <span class="pl-c1">0.3</span>, <span class="pl-c1">0.3</span>, <span class="pl-c1">1.0</span>]
<span class="pl-k">for</span> <span class="pl-s1">n</span>, (<span class="pl-s1">af</span>, <span class="pl-s1">ae</span>) <span class="pl-c1">in</span> <span class="pl-en">enumerate</span>(<span class="pl-en">zip</span>(<span class="pl-s1">alpha_faces</span>, <span class="pl-s1">alpha_edges</span>)):
    <span class="pl-s1">plt</span>.<span class="pl-en">plot</span>(<span class="pl-s1">n</span>, <span class="pl-c1">0</span>, <span class="pl-s1">ms</span><span class="pl-c1">=</span><span class="pl-c1">20</span>, <span class="pl-s1">mew</span><span class="pl-c1">=</span><span class="pl-c1">5</span>, <span class="pl-s1">marker</span><span class="pl-c1">=</span><span class="pl-s">'s'</span>,  <span class="pl-s1">mfc</span><span class="pl-c1">=</span>(<span class="pl-c1">1</span>,<span class="pl-c1">0</span>,<span class="pl-c1">0</span>,<span class="pl-s1">af</span>), <span class="pl-s1">mec</span><span class="pl-c1">=</span>(<span class="pl-c1">0</span>,<span class="pl-c1">0</span>,<span class="pl-c1">1</span>,<span class="pl-s1">ae</span>))
    <span class="pl-s1">plt</span>.<span class="pl-en">text</span>(<span class="pl-s1">n</span>, <span class="pl-c1">0.01</span>, <span class="pl-s">"$<span class="pl-cce">\\</span>alpha$ edge: {}<span class="pl-cce">\n</span>$<span class="pl-cce">\\</span>alpha$ face {}"</span>.<span class="pl-en">format</span>(<span class="pl-s1">ae</span>, <span class="pl-s1">af</span>),
            <span class="pl-s1">va</span><span class="pl-c1">=</span><span class="pl-s">'bottom'</span>, <span class="pl-s1">ha</span><span class="pl-c1">=</span><span class="pl-s">'center'</span>)

<span class="pl-c"># a black line to make the transparency clearer</span>
<span class="pl-s1">plt</span>.<span class="pl-en">axhline</span>(<span class="pl-c1">0</span>, <span class="pl-s1">color</span><span class="pl-c1">=</span><span class="pl-s">'k'</span>, <span class="pl-s1">lw</span><span class="pl-c1">=</span><span class="pl-c1">3</span>, <span class="pl-s1">zorder</span><span class="pl-c1">=</span><span class="pl-c1">0</span>)

<span class="pl-s1">plt</span>.<span class="pl-en">xlim</span>(<span class="pl-c1">-</span><span class="pl-c1">0.5</span>, <span class="pl-s1">n</span><span class="pl-c1">+</span><span class="pl-c1">0.5</span>)
<span class="pl-s1">plt</span>.<span class="pl-en">show</span>()</pre></div>
<p dir="auto">Result:<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://camo.githubusercontent.com/8c8dda9b207ad3d7cbc577a1f01297a8936b73d275646ca064f0dfdf3e706eec/687474703a2f2f692e737461636b2e696d6775722e636f6d2f426c3568702e706e67"><img src="https://camo.githubusercontent.com/8c8dda9b207ad3d7cbc577a1f01297a8936b73d275646ca064f0dfdf3e706eec/687474703a2f2f692e737461636b2e696d6775722e636f6d2f426c3568702e706e67" alt="figure_1" data-canonical-src="http://i.stack.imgur.com/Bl5hp.png" style="max-width: 100%;"></a></p>
<p dir="auto">Versions: Ubuntu 12.04, python 2.7.3, matplotlib 1.4.3</p>
<p dir="auto">I also posted this as a <a href="http://stackoverflow.com/questions/31981331/matplotlib-how-to-set-transparency-of-markeredgecolor" rel="nofollow">question on SO</a>.</p>