For example, could I use chicken broth (that does not contain any actual chicken meat) to prepare a meal on Friday?  What about chicken bouillon?
No, and
no.  In December 2015, there was a closely related discussion elsewhere on CathInfo, as the Vigil of the Nativity (Christmas Eve) was nearly upon us.
I provided a Web address for a more recent, albeit more, um, partisan, statement on
traditional fast & abstinence:
    <
web.archive.org/web/20150429100201/http://www.stmichaels.org/fasting-laws.shtml>.
It's more focused on
when the various rules applied, but some excerpts are directly applicable herein (after omitting the obvious ones):
2. [...] On days of complete abstinence, meat and soup or gravy made from meat may not be used at all.
In a source that seemed reasonably authoritative (but for which I can't find a citation
now), I read that there's what seems to be a concession to--or recognition of--differences in culinary cultures: Use of
only the
rendered fat, drippings, or
grease (from the same animals whose broth, soup, or gravy is
not allowed) are
allowed only when used as a
substitute liquid cooking medium distinct from those of other cultures, notably butter (e.g.: French) or oil (e.g.: Italian). I doubt that, e.g., many servings of eggs & hash-browns were fried in extra-virgin olive oil out on the American frontier.
5. Eating between meals is not permitted, but liquids [other than those in item 2], including milk and fruit juices, are allowed.
The source I'm excerpting is apparently squeamish about pointing out in item 5 that beer, wine, and other
alcoholic beverages are, in fact, also
allowed. Recall monks in mediæval Europe, brewing beer or fermenting wine or distilling brandy as products whose sale can contribute to the upkeep of the monastery. Then, if you not reading this when it could impact your appetite, ponder the health risks from plain water that courses downstream to the monastery thro' a secular settlement that more-or-less surrounds its walls. And recall that it would be several--or many--centuries before the role of microscopic organisms in causing human diseases would begin to be understood. Be that as it may, for whatever is allowed to be eaten or imbibed, rules of fasting do not allow the
excessive quantities that indicate
gluttony or cause
drunkenness.
I was really asking for situations when you are eating out or eating processed food, and you're not really sure what's in it.
I had a few surprises related to that concern, in late December:
· Canned
cream-based clam chowder, which listed "chicken broth" among its ingredients.
· 
Shrimp-&-grits recipes on line, some from up-scale sources, for which all (maybe except 1) of nearly a half dozen used
bacon grease, a few then crumbling the crisply cooked bacon over the top. No olive oil for those folks, who were predominately from the U.S. South. I'll leave it to those here with formal theological training to explain whether or not a "don't ask" attitude is a morally defensible when sitting down to a breakfast or brunch menu in Charleston (S.C.)
-------
Note *: "[Re:]
Fasting and Abstinence this week - Christmas Eve but NOT Christmas Day",
in "Catholic Living in the Modern World" forum (f=8). Dec 23, 2015, 3:00 pm. <
www.cathinfo.com/catholic.php?a=topic&t=39269#p3>.
Note #: Many
early settlers of Charleston were the French heretics known as
Huguenots, so I wouldn't be surprised if catering to "papist" traditions were not a (collective) cultural priority there.