Minimum distance

The minimum distance prefix specifies the minimum distance a player has to be from the entity, for the main tag's effects to take place.

Using minimum distance prefixes

Minimum distance prefixes use the format %n.., where %n is the minimum distance in blocks a player has to be from the entity.

speed255 supports the following distances to use with this prefix:
1, 2, 3, 4, 8, 16, 32, 64

To summon an entity with a minimum distance prefix:
/summon villager ~ ~ ~ {Tags:["effects","32..+jump-boost-2"]}
Such an entity would have jump boost 2, as long as there are no players within 32 blocks range of it.