I'll add my 2 cents to the tip jar.
LTM exists because Access is inherently is based on two parts The two parts are the data tables and everything else you build (such as queries, forms, reports, macros, and modules). When you build a single-container (a.k.a. monolithic) DB, by default all tables are in the single container file as well as all of the interfacing stuff (queries, forms, reports... you get the idea). BUT Access allows you to SPLIT that monolithic file into two parts. The data goes into a "back end" file and the other items go in the "front end" file. When you do that you have to tell the front end where the back end went because that is ALSO where your data went. During the split, LTM automatically creates connection pointers for every table definition in the FE file to link to the appropriate table definitions in the BE file. A BE file created this way is still a file in "Access native data" format. With me so far?
Although there are technical penalties involved, you can split apart the tables into multiple BE files, which you can do for reasons of needing the room (because of Access addressing limits), special security requirements, and perhaps a couple of other far less common reasons. The biggest technical penalties have to do with Relational Integrity, because Access cannot impose RI between two tables in different files. The internal tables that would define that RI have no way to specify in which file the tables exist, so they can ONLY be local. LTM will help you connect to the multiple tables in those multiple files. Split that way, the multiple BE files are still in Access native data format.
Here is where Access gets more powerful. You can point to other types of tables that aren't necessarily Access native data format. For instance, if you have a proper driver for it, you can talk to SQL Server or MySQL or SQL Lite, all using ODBC. You can talk to non-Microsoft database engines too, such as ORACLE, Sybase, IBM DB2, and anything else compatible with ODBC. LTM understands ODBC connections and thus allows you to have a mixed-mode installation, with a native Access format FE file and whatever is on the other side of the ODBC for that foreign DB.
I once worked briefly, more as a trouble-shooter than a full-blown DBA, on a U.S. Navy medical personnel database with an Access FE and an ORACLE BE. It handled the Navy's medical scholarship program where students would agree to work as a Navy doctor for 10 years in return for full tuition. If the U.S. Navy thought it was OK to use an Access FE and another BE, I guess it was OK for us, too. And LTM is how you set up that linkage.