```json
{
    "no": ["no"],
    "yes": ["yes"]
}
```

Based on the given description, the feature "zab_leg_02" represents the presence or absence of chronic bronchitis in the patient's medical history. For the task of determining whether the patient has chronic heart failure, the value of this feature does not provide direct information.

Since the feature "zab_leg_02" is binary with categories "no" and "yes", the presence of chronic bronchitis is indicated by "yes" and its absence is indicated by "no". Therefore, the possible values of "zab_leg_02" for the target class "no" are ["no"], indicating the absence of chronic bronchitis. Similarly, the possible values of "zab_leg_02" for the target class "yes" are ["yes"], indicating the presence of chronic bronchitis.

Note that the values for the feature "zab_leg_02" do not directly indicate the presence or absence of chronic heart failure. Hence, the dictionary contains only a single value for each target class.