Love
Not a feeling you generate. What is left when the fear is gone.
This is where My Big TOE departs most sharply from everything else in this genre, and it is worth being exact. The glossary defines love as the opposite of fear and as being about other — compassion towards, and caring about, someone else. Awareness expressing an intention to be caring, helpful and useful.
The mechanism is subtractive rather than additive. The material states it directly: love is nothing you have to attain and nothing you have to add. Get rid of the fear, and what remains is love.
It also rules out the usual synonyms. Romantic love is excluded because it implies need. And the word should never need the qualifier unconditional, because unconditional love is the only kind there is — if it has conditions, it is something else.
Where this gets misread
That the practice is to generate warm feelings towards people. Under this model that is exactly backwards, and it is why you will not find a loving-kindness exercise anywhere in this app. The material's position on self-love is narrower still, and worth reading in its own words rather than a paraphrase: it treats loving yourself as narcissism, and allows only the first step of not feeling negative about yourself.