How does this Javascript work (Part II)?

Here's my code:

define(['/assets/js/views/app2/custom_checkbox_and_radio.js','jquery'],function(){
    return function(){
      $('.at_filters label').click(function(){
        $(this).siblings('.checkbox').click();
      });
      $('input[name="filt"]').on('change',function(){
        if(this.value=='all'){
          if($(this).is(':checked')) $('input[name="filt"]').attr('checked', true);
          else $('input[name="filt"]').attr('checked', false);
        } else {
          $('input[name="filt"][value="all"]').attr('checked', false);
        }
        var show = [];
        var left = true;
        $('input[name="filt"]:checked').each(function(){
          show.push($(this).val());
        });
        var year = '';
        var month = '';
        $('.at_timeline_list li').each(function(){
          if($(this).hasClass('yearheader')){
            if(year && year.data('delete')) year.slideUp();
            else if(year) year.slideDown();
            year = $(this);
            year.data('delete', true);
          } else if($(this).hasClass('monthheader')){
            if(month && month.data('delete')) month.slideUp();
            else if(month) month.slideDown();
            month = $(this);
            month.data('delete', true);
          } else if($(this).hasClass('event')){
            if(show.indexOf($(this).data('type'))!=-1){
              $(this).removeClass('left').removeClass('right');
              $(this).addClass(left?'left':'right');
              left=!left;
              if($(this).css('display')!='list-item') $(this).slideDown();
              year.data('delete',false);
              month.data('delete',false);
            } else {
              if($(this).css('display')=='list-item') $(this).slideUp();
            }
          }
        });
        if(year && year.data('delete')) year.slideUp();
        else if(year) year.slideDown();
        if(month && month.data('delete')) month.slideUp();
        else if(month) month.slideDown();
      });

      //Account Search
      $('input.at_search').keypress(function(e){
        if(e.which == 13){
          $(this).siblings('.magnificon').click();
        }
      });
      $('.at_searchwrap .magnificon').click(function(){
        if(!$('.at_search').val()) return;
        pf.ajax({
          url:'/app/accounttimeline',
          data:{searchfor:$('.at_search').val()},
          type:'post',
          dataType:'json',
          success:function(res){
            if(res.success && res.body){
              if(res.loadAccount){
                pf.apps.loadApp({
                  appurl:'/app/accounttimeline',
                  postdata:{accountkey:res.loadAccount},
                  refresh:new Date()
                });
              } else pf.dialog(res.body, 'Search Results');
            } else {
              pf.dialog('There has been an issue processing your request. I apologize for the inconvenience, please try again.', 'Error');
            }
          }
        });
      });

      setupLabel();
    };
});

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I'm breaking it down in pieces. Thus far, we've defined a series of buttons and coupled some functionality to those buttons which includes a collection of functions. The first one is immediately after the "return function" code at line 6...

Lines 3-5 are a clunky way of associating a function with the "label" span, and then we're stating that all checkboxes that are associated with the label span are triggering the function that begins on line 6.

This first part:

$('input[name="filt"]').on('change',function(){
        if(this.value=='all'){
          if($(this).is(':checked')) $('input[name="filt"]').attr('checked', true);
          else $('input[name="filt"]').attr('checked', false);
        } else {
          $('input[name="filt"][value="all"]').attr('checked', false);
        }

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...is saying that if any of the checkboxes named "filt" (which is all of them) have a value of "all," then all of the checkboxes are to be checked.

Here's the HTML code for that part of the page:

 <ul class="at_filters">
      <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="all" checked/>
        </span><label>All</label>
      </li>
      <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="transaction" checked/>
        </span><label>Transactions</label>
      </li>
      <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="statement" checked/>
        </span><label>Statements</label>
      </li>
      <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="note" checked/>
        </span><label>Notes</label>
      </li>
      <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="comment" checked/>
        </span><label>Task Comments</label>
      </li>
	  <li>
        <span class="checkbox">
          <input type="checkbox" name="filt" value="personal_payments" checked/>
        </span><label>Personal Payments</label>
      </li>
    </ul>

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Now, this part of the code is where I'm getting fuzzy:

 var show = [];
        var left = true;
        $('input[name="filt"]:checked').each(function(){
          show.push($(this).val());
        });
        var year = '';
        var month = '';

We establish two variables, which I'm thinking will coincide with the CSS attributes that are attached to the different "<li>'s." But can you break it down for me?

I see the "filt," and I'm assuming that when one of the "filts" is checked (based on the "onchange" dynamic mentioned earlier), then the value associated with that checkbox (all, transaction, statement, notes, etc) is "pushed," right?

What is "show.push?"