Partial Answer to this mystery:

To see part of this code/string, you must install the plugin "cbplug_lang_cbsubs_english.zip" and visit the newly installed directory at ../components/com_comprofiler/plugin/language/cbpaidsubscriptionsenglish/english.php

You might not be likely to install this if (like moi) you saw that the plugin default_language-english is installed with the main CBSubs installment. In the doc it mentions installing if you want to translate from English or change the strings (but if you assumed that default_language English would have covered you them you'd be stumped).

However, this part of the string (the part several of us want to edit/change), is not in the file english.php This part:

"We suggest subscribing to following subscriptions"

Only the first part of the string is in there--I've searched and searched. So I wonder if there is an error file or wherever it might come from. Can't find it.