Migrated Magento 1 into Magento 2 does not seem to contain any 'default' Magento 2 email templates (using the Magento 2 migration tool). It only contains the Magento 1 email templates that were migrated.
(If this Magento 2 installation had it, I could have used them as reference)
None of the templates variables work in Magento 2 when previewing or emailing.
The following Magento 1 email template (account registration completed):
<!--@subject Welcome, {{var customer.name}}! @-->
<!--@vars
{"store url=\"\"":"Store Url",
"var logo_url":"Email Logo Image Url",
"var logo_alt":"Email Logo Image Alt",
"htmlescape var=$customer.name":"Customer Name",
"store url=\"customer/account/\"":"Customer Account Url"}
@-->
<!--@styles
body,td { color:#2f2f2f; font:11px/1.35em Verdana, Arial, Helvetica, sans-serif; }
@-->
<!-- truncated Html just to get to relevant sections @-->
<table>
<a href="{{store url=""}}"><img src="{{var logo_url}}" alt="{{var logo_alt}}" style="margin-bottom:10px;" border="0"/></a>
<td valign="top">
<h1>Dear {{htmlescape var=$customer.name}},</h1>
<h3>Account Registration successfully completed.</h3>
Results in this : 
Magento 2 articles found does not mention anything about Magento 1 migrated templates.
I checked the following articles, but mostly they just discuss changes between Magento 2 versions:
None of those assist me in changing Magento 1 variables into Magento 2 versions.
Question
Where / how can I find the equivalent versions.
For instance this template has {{var logo_url}}, {{var logo_alt}}, {{htmlescape var=$customer.name}}
A reference, or a way to browse the code to find the what is the customer/order/email address/etc variables versions of Magento 2.
