In former times, all Lego sets used to come with a small catalog. This was either just a single leaflet with an overview of several themes (with a focus on new sets or subthemes), found in smaller sets, or a small booklet like a smaller version of the main catalog, just restricted to "minifig size" sets (when buying one of those minifig sized sets) and usually without any product descriptions (just set numbers), included in larger sets.
Personal nostalgia anecdote: These catalogs were significant to me as a child because they would often grant the first glimpse at new sets of the upcoming year during the first few weeks of January before toy stores would get the first main catalogs.
Recently, I noticed that current sets do not include this kind of catalogs anymore. When did TLC change this habit?