File Number 1     <bx_include_base:../modules/base/text/template/breadcrumb.html />

File Number  2   <bx_include_base:../modules/base/general/template/breadcrumb.html />

File Number 3     <div class="bx-base-general-breadcrumb">

    <a class ="bx-base-general-breadcrumb-home" href="__url_home__"><i class="sys-icon __icon_home__"></i></a>

    <bx_repeat:items>

        <i class="sys-icon chevron-right bx-def-margin-sec-leftright"></i><a href="__url__">__title__</a>

    </bx_repeat:items>

</div>

File Number 4     <div class="bx-base-text-breadcrumb">

<a class ="bx-base-text-breadcrumb-home" href="__url_home__"><i class="sys-icon __icon_home__"></i></a>

<bx_repeat:items>

<i class="sys-icon chevron-right bx-def-margin-sec-leftright"></i><a href="__url__">__title__</a>

</bx_repeat:items>

</div>

Four different UNA files are named: breadcrumb.html. The code in each one is above. In UNA 13, something seems to have changed. Could be just a file path. 

Question 1 Which of the Files above are still in use? 

Question 2 Where should they reside?

Question 3 To implement breadcrumbs, do you still have to begin in Developer / Pages or can you use the plain Studio / Pages module?