I've been trying to figure out what this means. Here is an explanation I found:

A player who is signed to a contract with an Exhibit 10 will receive a bonus up to $50,000 if he signs a contract with the team's G League affiliate upon being waived from the parent club.
However, there is a catch. A player waived by Oct. 17 must report to his G League affiliate by Oct. 20 and remain there for at least 60 days to receive the bonus (in addition to the G League salary). Unlike last season, when a team would incur a salary-cap hit for players with partially guaranteed money who were eventually waived at the end of training camp, an NBA team will not have a cap charge for the bonus money awarded.
A player signed with an Exhibit 10 can also be converted to a two-way contract by the first day of the regular season. The bonus would then be rescinded and the two-way contract would apply.

Since the G-League salary is 35K, Rayjon could make up to 85K if he is waived and plays for the Bucks G-League team. The reason for these contracts is to entice players to stay in the G-League instead of going overseas. A team can offer up to 6 Exhibit 10 contracts. If Rayjon gets a 2-way contract (each team can sign two players to this type of contract) he would make 204K. If he actually make the Bucks roster he would likely make the league minimum of 507,336. It appears that the Bucks have 2 players under 2-way contracts at this time. I don't know if those are guaranteed or if Rayjon could still get one of those. I assume the first option above, is most likely, unless he really impresses in the preseason camp. It does appear that the Bucks see a lot of potential in Rayjon and want to keep him around.