Use of '&' as table prefix in query

Long ago I wrote a query which was greatly improved (i.e., it actually
worked as intended) by help here):

/* This query selects all activity information for a named person */

SELECT p.lname, p.fname, p.loc_nbr, p.job_title, p.direct_phone, p.active,
o.org_name,
l.loc_nbr, l.loc_name,
a.act_date, a.act_type, a.notes, a.next_contact
FROM People AS p
JOIN Organizations AS o ON o.org_nbr = p.org_nbr
JOIN Locations AS l ON l.org_nbr = o.org_nbr and l.loc_nbr = p.loc_nbr
JOIN Activities AS a ON a.person_nbr = p.person_nbr
WHERE p.lname = &p.lname AND p.fname = &p.fname;

I did not save the reason why the ampersand is used in the WHERE row selection
phrase and want now to learn why it's there. Probably needed to concatenate
separate names?

TIA,

Rich