I'd like to attach a javascript library to every page call. I created a directory for my module called flot_d8
I created an info file, lot_d8.info.yml. My understanding is, the libraries section should insert the javascript on every page load:

 name: FLOT-D8
 type: module
 description: 'This module provides a wrapper to the javascript FLOT library.'
 package: Misc
 version: 8.x-1.0
 core: 8.x
 hidden: false
 libraries:
 - flot_d8/flot

The library file which describes the flot asset is flot_d8.libraries.yml. I placed the flot library in drupal/modules/flot_db/flot:

 flot:
 version: 1.x
 js:
 flot/jquery.flot.js: {}
 dependencies:
 - core/jquery

I enabled my module and fail to see the inclusion of jquery or foot in the header. My next attempt was to make a flot_d8.module file with a call to hook_page_attachment_alter:

 <?php
 function flot_d8_page_attachments_alter(array &$page) {
 // Attach the flot asset on every page.
 $page['#attached']['library'][] = 'flot_d8/flot';
 }

Still no dice. Any advice? I'm wanting to begin playing around with getting the flot library working in D8. I'll eventually move the javascript attachment to occur during themeing, but I don't want to attempt that until I can even get the simplest case working.

As background. I've installed the PHP module so I can enter PHP directly into a page. If I insert the scripts and add javascript directly in the page. it works fine. This tells me the files are in the webspace and readable by the outside world:

 <script src="http://test.mysite.com/core/assets/vendor/jquery/jquery.js"></script>
	<script language="javascript" type="text/javascript" src="http://test.mysite.com/modules/flot_d8/flot/jquery.flot.js"></script>
	<script language="javascript" type="text/javascript" src="http://test.mysite.com/modules/flot_d8/flot/jquery.flot.pie.js"></script>
 <script type='text/javascript'>//<![CDATA[
 $(window).load(function(){
 $(function () {
 var d1 = [];
 for (var i = 0; i < 14; i += 0.5)
 d1.push([i, Math.sin(i)]);
 
 var d2 = [[0, 3], [4, 8], [8, 5], [9, 13]];
 
 // a null signifies separate line segments
 var d3 = [[0, 12], [7, 12], null, [7, 2.5], [12, 2.5]];
 
 $.plot($("#placeholder"), [ d1, d2, d3 ]);
 });
 });//]]> 

 </script>
 <div id="placeholder" style="width:600px;height:300px;"></div>